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Re: 94 Accord and fuel pump relay symptoms...sorta, see post
| Tegger | 10 Feb 2008 10:44 |
> : > Anyone ever repair a funky ECM by opening it up and cleaning up > : > any bad solder joints? Will the ECM avoid sending fuel if it sees [quoted text clipped - 16 lines] > few minutes and it starts working. The ECM isn't pulling the second > relay down :( Disconnect the Main Relay's plug from the Main Relay. Connect a multimeter (set to Ohms) between the plug's Terminal 8 and a body ground.
Turn the key to "II". At thre same time as you turn the key, watch the multimeter carefully. Do you get continuity for two seconds?
Have you checked the ECU ground at the thermostat housing? Have you checked the engine grounds at the transmission housing and from valve cover to shock tower?
 Signature Tegger
The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/
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| Howard Goldstein | 09 Feb 2008 18:36 |
: Howard Goldstein wrote: : > Anyone ever repair a funky ECM by opening it up and cleaning up any : > bad solder joints? Will the ECM avoid sending fuel if it sees : > something "wrong" at its sensors although there aren't any codes : > stored? Should I toss the ECM at this point? : > : > Long nauseating details and plea follow: : > : : -------------------- : : If you sit there with key in position II and nothing happens (no fuel : pump), smack the dash on the left side. If the fuel pump goes : GzzzzzzCLICK, the car will now start. They NEVER fail while the engine : is running because the vibration makes the bad solder connection work : enough. : Resolder or replace the relay.
Hi, we chatted about this a few months ago. Neither resolder nor replace makes no difference. Sitting there with the key on II for a few minutes and it starts working. The ECM isn't pulling the second relay down :(
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| motsco_ | 09 Feb 2008 18:29 |
> Anyone ever repair a funky ECM by opening it up and cleaning up any > bad solder joints? Will the ECM avoid sending fuel if it sees > something "wrong" at its sensors although there aren't any codes > stored? Should I toss the ECM at this point? > > Long nauseating details and plea follow: --------------------
If you sit there with key in position II and nothing happens (no fuel pump), smack the dash on the left side. If the fuel pump goes GzzzzzzCLICK, the car will now start. They NEVER fail while the engine is running because the vibration makes the bad solder connection work enough. Resolder or replace the relay.
'Curly'
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| Howard Goldstein | 09 Feb 2008 13:06 |
Anyone ever repair a funky ECM by opening it up and cleaning up any bad solder joints? Will the ECM avoid sending fuel if it sees something "wrong" at its sensors although there aren't any codes stored? Should I toss the ECM at this point?
Long nauseating details and plea follow:
Recap: 94 Accord with the classic main relay (PGM-FI) symptoms (no fuel pump sound for 2 seconds as required when starting, check engine light on, can't start) with a twist: It only fails in a cold car when ambient is around above about 70F/27C, *and* leaving the key in the II (IGN) position for anywhere from 1 to 4 minutes has always allowed the second relay and then the fuel pump to kick in, CIL goes off and we're off. Never a problem while driving, and if the engine is warm it's never a problem starting. It also isn't a problem when the entire car has cooled to the low 60s/low 20s F/C or below. Cranking it doesn't help.
What I've done: I've verified there's no 12v back at the fuel pump when this happens but for good reasonI've measured battery voltage at the relay pins 6 (good) and 1 (bad) and back at the ECM A25&B1 and A7 (these are the connections to the relay) where it's good and bad (both at Vbatt). I've jumpered the service connector and the CIL stays on all the time. I've got good grounds at the ECM A connector and the PGM-FI.
What seems to be busted: WTF is up with my ECM? The skiz show the fuel pump relay in the PGM-FI won't close unless the ECM pulls down its A7 (which is PGM-FI pin 1). It doesn't pull it down, not unless the car is left in II/IGN for a couple of minutes under the conditions above.
Some specific questions:
- What else am I missing?
- Does the ECM look for other things, a sensor in a sane range or something other than battery voltage coming off of PGM-FI 6, before it'll turn on the fuel pump for the 2 seconds?
- Is it worth cracking open the ECM to reheat any obviously flakey solder joints? Can the ECM be cracked open easily?
- Anyone have a compatible ECM they'd loan me to do a swap check if I've ruled out everything else?
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