My 90 Suburban R2500, 2wd, 454 cid, has a hard start problem. After she
turns over for approximately 10-15 seconds, she backfires and begins
running. There is a strong smell of gas after she starts, but once I get her
on the road she runs and idles without problems ... other than very poor
fuel economy.
I am suspecting the fuel pressure regulator and/or the relay. I am not sure
if this is true, but to test the regulator I need to remove the vaccum line
and rev the engine to see if fuel spills from the line. Is this correct?
Where on the engine is the regulator located? The relay I am familiar with
and it seems to be clicking on and off when the engine primes itself, so I
am doubtful if that's the problem.
If anyone has any other ideas, please chime in!
Thanks,
Andrew
TranSurgeon - 08 Nov 2004 19:23 GMT
TBI ?
then it is internal to the TB
> My 90 Suburban R2500, 2wd, 454 cid, has a hard start problem. After she
> turns over for approximately 10-15 seconds, she backfires and begins
[quoted text clipped - 13 lines]
> Thanks,
> Andrew
Andrew Ross - 08 Nov 2004 19:46 GMT
Yes, that's correct, it is throttle body injection. When you say "internal",
can I reach it without any special tools? Where on the throttle body is it
located? Do you think this is the problem?
Thanks,
Andrew
TranSurgeon - 08 Nov 2004 19:53 GMT
it is internal
I've never disassembled one
> Yes, that's correct, it is throttle body injection. When you say "internal",
> can I reach it without any special tools? Where on the throttle body is it
> located? Do you think this is the problem?
>
> Thanks,
> Andrew
Andrew Ross - 08 Nov 2004 21:43 GMT
Anyone know how big a job this is and if I can do it myself? Do the symptoms
I described sound like this might be the problem?
Thanks,
Andrew
Andrew Ross - 09 Nov 2004 00:03 GMT
Ok, just an update. I tried to pull codes but nothing is showing. As far as
the computer is concerned, everything is normal.
Andrew
r_d - 10 Nov 2004 03:20 GMT
> Ok, just an update. I tried to pull codes but nothing is showing. As far
> as
> the computer is concerned, everything is normal.
>
> Andrew
I suspect you have the same problem that I do. As the injectors get older
they start to leak. So once you shut off the truck the fuel system
depressurizes itself by leaking out the injectors into the intake. So in
fact the truck is flooding. You can get a kit to rebuild the TBI unit and
replace the two injectors but it probably will be as expensive just to get a
rebuilt one from an autoparts house. Anyway, you can get to the pressure
regulator easily (on top of the TBI) and if you get a rebuild kit make sure
it does come with the regulator diaphragm (some do some don't, make sure you
get the one that does). Just rebuild it and use the old injectors and see
how you make out. If it still does it then replace the injectors. Make
sure you do remove the TBI before you pull any screws and rebuild it on the
bench...
Good luck,
mark
Andrew Ross - 11 Nov 2004 03:50 GMT
Thanks for the information.
If I give it to a shop, do you think they will be able to diagnose the
problem, even if the TBI needs rebuilt?
Thanks,
Andrew