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Car Forum / Chrysler Cars / August 20051990 Dodge Grand Caravan 3.3l V6 Stalling/rough idle
I have a 1990 Dodge Grand Caravan with about 130,000 Miles on it. It has Chrysler's 3.3L V6 engine. Recently, I've had an issue with it idling. What happens is that the idle will drop to about 300 RPM for a second, then it will shoot up to about 1000 RPM, then it will fall to the normal 600 RPM for about a second, and repeat. A few times it has outright stalled. Unfortunately, this is intermittant. It has only happened after the engine has sat a few hours (though it's only happened 4 times or so, so it may be concidence) or it may be related to a cooler engine temp. When it's happened, hitting the gas to bring it up to about 3000 RPM, then letting it fall back to idle seems to fix it - the car will happily idle then. Anything above idle and the car runs fine. The idle is a BIT rough, but keep in mind it is 15 years old. No violent shaking or anything, but not perfectly smooth like a new car would be. I've used my scan tool (Actron CP9150) and no faults are being logged. The voltage on the TPS does change, but I haven't had the tool on it while the fault is actually occuring (what idiot put the connector under the hood! :-P ) This happened once about 2 months ago, and I asked around and was told to clean the throttle body. So we took off the throttle body, cleaned all the gunk out, put it back together and it didn't happen after that, so I assumed it was fixed. Then this started happening this afternoon. I also should note that we did change the timing chain a few days ago. I doubt it is related, as this did occur once before back in december (though the car wouldn't idle at all then, just started and died) but figure I should mention that. Any thoughts/suggestions/tests would be appreciated. Thanks, Eric Kotz newsgroups@erickotz.com > I have a 1990 Dodge Grand Caravan with about 130,000 Miles on it. It > has Chrysler's 3.3L V6 engine. Recently, I've had an issue with it [quoted text clipped - 27 lines] > Eric Kotz > newsgroups@erickotz.com What step is the AIS motor on, 16 is a good number with the a/c off and a clean throttle body. > while the fault is actually occuring (what idiot put the connector > under the hood! :-P ) What idiot made an after market scan tool with such a short wire after it was designed for the DRB? Was the Tamper proof plug removed on the Screw that adjusts the throttle blade angle?? Glenn Beasley Chrysler Tech How do I read what step the AIS motor is on? I have a TPS voltage reading (which is at .57v at idle) but I didn't see anything about the AIS motor? The scan tool has a 6 foot cable - hardly long enough to reach out the front of the hood and back into the passenger compartment. Unfortunately, yes, the tamper proof plug has been removed that protects the throttle blade angle. How can I properly reset it? > How do I read what step the AIS motor is on? I have a TPS voltage > reading (which is at .57v at idle) but I didn't see anything about the [quoted text clipped - 4 lines] > Unfortunately, yes, the tamper proof plug has been removed that > protects the throttle blade angle. How can I properly reset it? Have you thought about extending the cable? If it's a ribbon, it should not be terribly difficult although you might want to ask someone who fixes or does electronics. There are lots of different connectors and cables, flat ribbons and what not, but you need to order from electronics warehouses. Radio Shack has close to nothing, unless you are very lucky, having driven all the little stores out of business, as Walmart's is doing big-time, so you can't find any electronics stores except Rat Shack now. Either adding on to the cable is safest, or cutting the cable in two, and adding your own connectors. Almost never found any connector that was really proprietary. But I can remember going through AMP catalog looking for weird connectors, but found them and ordered them from Newark or Digi-Key = DigiKey.com [used to be a really patient company for newbies - find parts and so on]. If this goes well, maybe a small business set up here? Must be lots of other people who want to extend their devices. Unless and this is a big unless the device is not stable with more than six feet of cable. This can happen but with very good cable, usually low capacitance, they almost always can be extended. I remember when printer cables had to be six feet, but now I see them as long as 50 feet or 25 feet without amplifiers. I barely know what an AIS motor is so can't help with the auto part of your question. I was out today with my mostly trusty 1990 Dodge Grand Caravan when I stopped for lunch. After an hour, or so, I returned to the van and turned the key to start. It usually fires right up, but it turned over smartly (a very young & strong battery) but did not start. I tried several times and finally it began to cough and then started, but unless I kept pumping the throttle it would die. I repeated this procedure several times and finally it died and wouldnt start again. I had it towed to my house. I first thought that the computer (SBEC?) was at fault in not maintaining an idle, but then thought that the fuel pump may have quit and the short times getting the engine to run briefly was due to residual fuel in the lines and injectors. It's an old, but very useful car that can't sell for the cost of an expensive repair. I am not equipped to drop the tank and change the fuel pump, but what can I do to test that possibity? I have the factory shop manual, but I sure don't have the factory test equipment that the manual says is meant to measure fuel pressure. I won't take (tow) it to the dealer sharks, but I fear even the most reasonable service centers will be too much. Like all others who suddenly can't breathe life into their "trusty steed" I sure don't need this right now.... (But Who Does? ;-) ) What would you do? Celtfire celtfire1@cox.DOO-DAHnet of course, dump the DOO-DAH I see that the professional mechanics haven't jumped on this one yet, so I'll throw in my two cents. You say that it did something that qualifies as "almost running", so it isn't likely a catastrophic failure of some component or another. Could be a fuel filter problem. Did it ever exhibit symptoms of not quite having enough mojo when you started going up a slight incline on the freeway? I had a van that did that for a while. On a slight incline that should have posed absolutely no problem, it would not maintain the 65 mph cruise control setting but would gradually slow down while the cruise control pulled the pedal down to the floor. Then one day when I tried to start it, it quit just like yours. Have you seen this type of behavior in your van? How about any other little quirky things? Any additional info would help, if you can think of anything. And just to make sure, when you turn the key to "ON" do you hear the fuel pump turn on for a second or two in the fuel tank? > I was out today with my mostly trusty 1990 Dodge Grand Caravan when I > stopped for lunch. After an hour, or so, I returned to the van and [quoted text clipped - 26 lines] > celtfire1@cox.DOO-DAHnet > of course, dump the DOO-DAH >I see that the professional mechanics haven't jumped on this one yet, so >I'll throw in my two cents. You say that it did something that [quoted text clipped - 12 lines] >And just to make sure, when you turn the key to "ON" do you hear the >fuel pump turn on for a second or two in the fuel tank? Thanks for the input, Robbie. After letting the it sit in the driveway for almost 24 hours I tried to start the car today. It fired up and then stalled out. I got it started again and lept it running for about 20 seconds by accererating the rpm's to about 3000. It then died on its own while I was still giving it gas. I believe that the fuel pump is probably OK so what does that leave me for probable cause? The computer seems a likely culprit. The car was running brilliantly before yesterday afternoon. It always had power on the flat or on hills and could easily cruise at 80 mph (128.75 kph). I don't believe I can keep it running on the road unless I crash all stop lights and signs on the way to a mechanic, so I'd better get a tow. Any other ideas out there? Mr. Stern? > After letting the it sit in the driveway for almost 24 hours I tried > to start the car today. It fired up and then stalled out. I got it [quoted text clipped - 3 lines] > does that leave me for probable cause? The computer seems a likely > culprit. Sounds like a classic fuel pump problem or a clogged fuel line. What makes you so certain the fuel pump is good and why do you suspect the computer? Do you have any error codes set? Have you tested the fuel line pressure when it is stalling? Bob >> After letting the it sit in the driveway for almost 24 hours I tried >> to start the car today. It fired up and then stalled out. I got it [quoted text clipped - 8 lines] >Do you have any error codes set? Have you tested the fuel line pressure >when it is stalling? Using the on-off method I received a 55, or no error codes. I started the van again today and by keeping it running between 3000 - 4000 rpm it kept going for almost two minutes. At that point I gradually eased off the accelerator and at about 2000 rpm it died. Two days ago the problem first presented when I tried to start it after running trouble free for 50,000 miles, or so. Now I can't believe that the problem is a fuel pump or filter. I've had a pump go out on this vehicle several years ago. At that time it ran fine, I stopped for a few minutes and when I tried starting it turned over but never gave a hint of spark igniting fuel. Nada! In that case I figured fuel pump and the mechanic's test proved me right. In its present injured condition it will start after sitting for awhile, but won't keep running unless I give it a lot of gas pedal. I'm a "shoemaker mechanic," in that I can usually fix the nuts n' bolts kinds of things, but the more complicated analysis and repair is a bit beyond me, BUT I do hope to have a good idea of what truly ails the car so that the chosen service facility doesn't succeed in hornswoggling me with expensive and unnecessary solutions. I will change the fuel filter and see what, if any, changes result. Thanks for all advice. I really appreciate the community here on rec.autos.makers.chrysler. > > After letting the it sit in the driveway for almost 24 hours I tried > > to start the car today. It fired up and then stalled out. I got it [quoted text clipped - 8 lines] > Do you have any error codes set? Have you tested the fuel line pressure > when it is stalling? I'm thinking it sounds like a fuel pump, too. I had an 88 Voyager that had an intermittent fuel pump problem. On a few occasions, it was running and then it turned itself off and wouldn't turn back on until the next day. The last time this happened I had left it and gotten a ride home, then I went back across town the next day to retrieve the van. I started it up and headed for home on the freeway, but when I slowed down for a curve, lower demand caused the pump to stop and it didn't start back up, so I ended up with a dead van on the highway. If it hadn't been for that stupid curve I would have made it a lot closer to home... Anyway, it was the fuel pump causing the problem. And I suspect that an excessively old filter might have helped the pump reach the end of its useful service life. I still think that when your van quits and you determine that it isn't going to start again, you should come back in ten minutes and turn the key to "ON" to see if you can hear the pump. If it's working as it should, you will hear a friendly sounding "bzzzzzt" noise from the gas tank. It's easily audible from the driver's seat. If you hear nothing, then you have a problem with the pump. When was the last time you changed the fuel filter?? That's what it sounds like to me. Have had similkar experiences, changed out fuel filter, and all was well with the world. Hope this helps. > Any other ideas out there? Do yourself a favor and change the fuel pump. When they start to go bad they sometimes have weird symptoms including hard starting, stalling but running fine at 80 mph on the freeway. I know it doesn't make sense but it's true. So, if you must be convinced, go down to Autozone, or the equivalent, and rent/borrow a fuel pump pressure gauge. Hook it up to the fuel rail and see for yourself that your not getting the 45+ PSI fuel pressure needed. >> Any other ideas out there? > [quoted text clipped - 5 lines] >the fuel rail and see for yourself that your not getting the 45+ PSI >fuel pressure needed. I did. I'm not up to dropping the tank (neither is my wife or our community association) and all that so I scouted around and found a "recommended by several," close-to-home mechanic who quoted a price much cheaper than the dealer sharks did. I hope that changing the pump and filter (Idid that earlier today) make the "old gir"l run better. Thanks for all the help > How do I read what step the AIS motor is on? I have a TPS voltage > reading (which is at .57v at idle) but I didn't see anything about the [quoted text clipped - 4 lines] > Unfortunately, yes, the tamper proof plug has been removed that > protects the throttle blade angle. How can I properly reset it? I have never used that generic scan tool and don't know what it is capable of doing, But I would assume if you can read voltages on it you should be able to read sensor values. And It should show what step it is on. If the throttle body was dirty and someone adjusted the Throttle blade angle/TPS sensor..... That may be your problem.. I normally put the system into a minimum air flow test and adjust the idle/sensor that way. Once again, not sure if your scanner is capable of doing that....Turn the screw out about a half turn to see if that stops it OK, I looked through the scan tool again and found that the AIS position is generally about 65-70 A couple new developments today. The engine seems to do it more when it is cold/not do it when it is warm. While it was doing it today, I had the oppertunity to hook my scan tool up and nothing looked terribly out of the ordinary, but it's hard to tell. While it was happening, the O2 sensor was reading rich. It also no longer seems to be an idle problem, as when I held my foot on the gas it was still having the issue, up to about 1500RPM. Past that it seemed fine. Also, one time I hit the gas and it seemed like the engine speed did not increase. Additionally, I heard 2 clunk noises coming from the engine at one point. Perhaps it was just backfiring, but it did sound like it came from the engine, not the exhaust. I plan on disconnecting the EGR valve today and seeing what happens, but any more insight is appreciated. > OK, I looked through the scan tool again and found that the AIS > position is generally about 65-70 [quoted text clipped - 12 lines] > I plan on disconnecting the EGR valve today and seeing what happens, > but any more insight is appreciated. 65 to 70 steps? thats too high, you need to get the the throttle blade set back and make sure the blade and bore is clean.Typically the out of adjusted TPS will cause problems when cold and could also cause a hestitation and other problems Can you give me any advice on re-setting it properly? My scan tool doesn't seem to have a minimum airflow test - are there any other things that test can be called? Failing that, is there another way I could set this screw properly? The blade and bore should be clean - about 2 months ago I took them off and used a toothbrush and about 1/2 a can of carb/choke cleaner to clean them and they were virtualy spotless. The van has only been driven about 1000 miles since then, so they should be clean. > Can you give me any advice on re-setting it properly? My scan tool > doesn't seem to have a minimum airflow test - are there any other [quoted text clipped - 4 lines] > clean them and they were virtualy spotless. The van has only been > driven about 1000 miles since then, so they should be clean. Back off the screw about a half turn, restart and see if that changes, if not back off some more and recheck, see if that makes a difference, Our scanner allows us to perform these tests by programed tests in the scanner. keep in mind that you may have other problems and it isnt related to the adjustment. Do you have a sensor value for adaptive fuel memory on your scanner? > Can you give me any advice on re-setting it properly? My scan tool > doesn't seem to have a minimum airflow test - are there any other [quoted text clipped - 4 lines] > clean them and they were virtualy spotless. The van has only been > driven about 1000 miles since then, so they should be clean. REPAIR PROCEDURE: This bulletin involves checking the throttle body calibration for settings that effect operation at idle. 1.. Remove the air cleaner. 2.. Remove the vacuum line from the PCV valve and install the 0.185 inch orifice tool, No. 6714 into the vacuum line. 3.. Disconnect the 3/16" canister purge hose at the front of the throttle body and cap the nipple. 4.. Install the Scan Tool (DRB II) and start the engine. Warm the engine to operating temperature. 5.. Using the Scan Tool (DRB II), scroll through the menus as follows: select - System, select - Engine, select - Fuel and Ignition, select - Actuator Tests, select - Engine RPM, select - Minimum Air Flow. The Scan Tool will count down to stabilize the idle rpm, and display the minimum air flow idle rpm. The Idle RPM should be between 500 and 900 RPM. If the idle is outside these specifications, replace the throttle body. 6.. Remove the Scan Tool. 7.. Remove the orifice tool and install the vacuum line on the PCV valve. 8.. Install the idle purge hose on the throttle body 9.. Install the air cleaner. The reason why it says replace the throttle body is because legally we cant remove the plug to adjust the angle, but when someone does tamper with it, here is a guidline to the proper setting to get it back, However this test is no good to you because your scanner sounds like it is just a read out box Well, what should I expect to see? I backed it out 1/2 a turn and when starting the engine the AIS was about 35. After running for a couple minutes, it worked its way down to about 30. Also, does this engine have an EGR valve? The service manual is unclear - it seems to imply that all US versions have it, but then has a California-specific section. I can't find the EGR valve - is it just not there, or am I just missing it. My scan tool can cause the AIS motor to move, but unfortunately it doesn't give me control over it (just cycles open-closed-open...) Thanks! > Well, what should I expect to see? I backed it out 1/2 a turn and when > starting the engine the AIS was about 35. After running for a couple [quoted text clipped - 6 lines] > doesn't give me control over it (just cycles open-closed-open...) > Thanks! the emission sticker under the hood will tell you if the vehicle is equiped with an egr valve or not, if it has one it would be just behind the throttle body on the bottom I assume you mean the sticker in the middle of the hood that says "This vehicle conforms to the US EPA regulations applicable to 1990 model year new light-duty trucks at all altitudes" and has a diagram of some of the emission stuff. There's no mention of an EGR valve - I would take it that means there is not one? Also what should I target for the AIS position - ie should I turn that screw further? It started at about 34 or so when I started the cold engine. After running for about 8 minutes it was down to 27 or so. Thanks! If it doesnt say it on the sticker, it has no EGR valve, unless the engine was swapped out with a used one,, leave the setting at that position and see if it makes a difference. 16 steps was a good setting for that yr > I assume you mean the sticker in the middle of the hood that says "This > vehicle conforms to the US EPA regulations applicable to 1990 model [quoted text clipped - 5 lines] > engine. After running for about 8 minutes it was down to 27 or so. > Thanks! OK, so no EGR valve then. Earlier today I took a bunch of connectors, unplugged them, shot some cleaner in them, plugged them back in. No difference :-( Also, when the engine is at full temperature, the AIS motor went down to about 18. The problem seems to manifest itself when the engine is warming up. Something like 110° through 135° coolant temperature. Engine seems to be fine when dead cold or hot, but unhappy while warming up. Problem no longer seems to be an idle problem - rather, a generic running problem. Also, I hear a whistling noise from the engine that seems loudest at about 1200RPM. Sounds like it could possibly be a vaccuum leak, but we can't find a source. It *SOUNDS* like it is coming from the bracket directly above the alternator - but obviously metal brackets don't have vaccuum leaks :-P I'd also like to point out the cam sensor was severely disturbed when we changed the timing chain. Chrystler's directions, for some reason, said to remove it, which we attempted to do. The stupid thing refused to come out. Ultimately we gave up on removing it and discovered there was no need to remove it anyway. Also, what is a normal value for the MAP sensor? My scan tool is showing about 275 Torr. Any more help would be much appreciated. Thanks, Eric Kotz newsgroups@erickotz.com OK, so no EGR valve then. Earlier today I took a bunch of connectors, unplugged them, shot some cleaner in them, plugged them back in. No difference :-( Also, when the engine is at full temperature, the AIS motor went down to about 18. The problem seems to manifest itself when the engine is warming up. Something like 110? through 135? coolant temperature. Engine seems to be fine when dead cold or hot, but unhappy while warming up. Problem no longer seems to be an idle problem - rather, a generic running problem. Also, I hear a whistling noise from the engine that seems loudest at about 1200RPM. Sounds like it could possibly be a vaccuum leak, but we can't find a source. It *SOUNDS* like it is coming from the bracket directly above the alternator - but obviously metal brackets don't have vaccuum leaks :-P I'd also like to point out the cam sensor was severely disturbed when we changed the timing chain. Chrystler's directions, for some reason, said to remove it, which we attempted to do. The stupid thing refused to come out. Ultimately we gave up on removing it and discovered there was no need to remove it anyway. Also, what is a normal value for the MAP sensor? My scan tool is showing about 275 Torr. Any more help would be much appreciated. Thanks, Eric Kotz newsgroups@erickotz.com Aww info coming......If you disturbed the sensor in any way trying to loosen it, you may have changed the air gap in it and this could cause problems....Did you say this problem was an after fact of the timing chain?.....And if its a vacuum leak, that could pose problems as well.. They say to remove the sensor so you don't break it and then install it back with the proper setting using a paper shim that sticks to the sensor as you install it. Do you have at least 18 inches of vacuum at idle? In article <1109906380.423909.30310@l41g2000cwc.googlegroups.com>, > Also, what is a normal value for the MAP sensor? My scan tool is > showing about 275 Torr. > Any more help would be much appreciated. 275 Torr equals (appx) 10.8 inches of mercury Assuming a baro reading of 29.X inches of mercury, that puts your manifold vacuum around 18 inches of mercury. If your scan tool gives a voltage reading for the MAP sensor, I'd expect to see it around 1.5 volts or slightly less... My question was somewhat different. Original Post mentioned changing the timing chain. Why was this done? My only experience with a chain was on my Saturn, and I had 170,000 miles with no suggestion from anyone that the chain should be changed...as long as we kept oil in the engine. Should I anticipate changing the chain on my Dodge 3.3 V6? At which point? And how much can I expect to pay to have a mechanic do that? Thanks. Barry in C'ville Driving my first Dodge. > In article > <1109906380.423909.30310@l41g2000cwc.googlegroups.com>, [quoted text clipped - 9 lines] > If your scan tool gives a voltage reading for the MAP sensor, I'd > expect to see it around 1.5 volts or slightly less... > My question was somewhat different. Original Post mentioned changing the > timing chain. [quoted text clipped - 24 lines] > > If your scan tool gives a voltage reading for the MAP sensor, I'd > > expect to see it around 1.5 volts or slightly less... There is no normal maintenance schedule for chain replacement, normally an 1/8 inch of stretch or when it rattles, I would say about 4 hrs labor, maybe 150.00 parts, don't quote me on that <snip> > Should I anticipate changing the chain on my Dodge 3.3 V6? At which point? > And how much can I expect to pay to have a mechanic do that? I've changed timing chains on 3.3s at 110K miles, I've seen vans with 200K that didn't need one. Maintenance goes a long way here. The chain stretch can be determined by labscoping the camshaft sensor and crankshaft sensor signals and comparing the two for offset. Labor charges to replace the chain depends on which generation mini-van you have, third generation being the hardest to do because of underhood access. I don't have my labor books handy, but I believe it's going to be higher than the 4 hours Glenn mentioned. Front motor mount has to come off as does the oil pan... If you want specific labor times, post the model year and I'll look it up tomorrow at work. FYI, it *SEEMS* it was the cam sensor. We gave it a couple taps to push it down a little more (after all, we were pulling on it trying to pull it out) and so far the problem has not happened at all today. So HOPEFULLY it was fixed. As to why we changed the timing chain - it was rattling. Just as a curiousity thing, I called Pep Boys and asked how much it would be and they told me something around $500. This is on a first-generation minivan. Thanks everyone! Eric Kotz newsgroups@erickotz.com I drive an '03 3.3 grand caravan...and I don't anticipate any problems... But I always want to know more about the machine I'm driving. Thanks. Barry > <snip> >> Should I anticipate changing the chain on my Dodge 3.3 V6? At which [quoted text clipped - 15 lines] > If you want specific labor times, post the model year and I'll > look it up tomorrow at work. |
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