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Thread: 1987 chevy 350tbi problems

  1. #1
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    Exclamation 1987 chevy 350tbi problems

    I have a 1987 chevy v10 350 TBI. I was having some mild looping at start up and sometimes at idle at stop lights. I started by replacing the spark plugs and wires, coolant sensor, and tps. I rebuilt the throttle body and flushed the injectors, replaced the fuel filter. I recently just replaced the egr with one from carquest that was specific for my old egr. After new egr installed ran ok for a a couple start ups and miles but next day started up and ran real bad looping. Almost like it wanted to die. Had to keep on throttle to prevent from dieing. The new egr is apperently adjustable so i twisted it and it seem to help for a minute put it in drive drove a few blocks and it was doin it again. Adjustment to egr dont help. Almost seems like the egr is letting too much exhaust back in to cylinders. Any suggestions? Please help.

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    Senior Member silverhairdeere's Avatar
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    Quote Originally Posted by nickcheck52 View Post
    I have a 1987 chevy v10 350 TBI. I was having some mild looping at start up and sometimes at idle at stop lights. I started by replacing the spark plugs and wires, coolant sensor, and tps. I rebuilt the throttle body and flushed the injectors, replaced the fuel filter. I recently just replaced the egr with one from carquest that was specific for my old egr. After new egr installed ran ok for a a couple start ups and miles but next day started up and ran real bad looping. Almost like it wanted to die. Had to keep on throttle to prevent from dieing. The new egr is apperently adjustable so i twisted it and it seem to help for a minute put it in drive drove a few blocks and it was doin it again. Adjustment to egr dont help. Almost seems like the egr is letting too much exhaust back in to cylinders. Any suggestions? Please help.
    when you changed out the egr did you clean out the port below , could be carboned up .
    SHD

    1989 GMC 1500 (PROJECT CHEAP TRUCK)

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    No i didnt but i looked in and didnt seem to be too bad. Also old egr wasnt this bad should i put the old egr back on and see if it goes bak to the way it was before?

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    Senior Member Stitz Love's Avatar
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    another fuel pump bites the dust?

    Your description of symptoms and your response to them all sound in line with the recent run of fuel pumps pooping out.
    Do you have access to a fuel pressure guage? If not there is a member who can send one to you.

    See threads titled "Code 44 - specifice issue" and "94 K1500 5.7 TBI - need help" and consider yourself welcomed to the forum.
    1990 Chevy Cheyenne, SB (2wd / AC) with a;
    1993 5.7 from Police Cruiser (LO-5)-(?) installed by previous owner.
    (It sat for 7 years before I bought it.)

  5. #5
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    Well it only has a really rough idle. If fuel pump was goin out then i would get studdering when i was on throttle too. I can go wot and hav no problem but wen im at idle its real rough

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    fuel pump failure would not be running at all. electric pump. if having an idle problem, i would look into a vacuum problem or a IAC that is failing.

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    Senior Member shadygrady's Avatar
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    Yeah,I`d make sure I got all my vacuume lines hooked up and in the right spot.
    1993 k1500 SWB reg.cab.5.7,4l60e.CAI,CAT!3" single exhaust from y-pipe to tip.3" in and out turbo muffler.

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    Ok ill look into my vacuum lines again. But anyone know where i can find the proper egr solenoid for 89 350 tbi? I think my egr vacuum solenoid might be stuck open but i cant seem to find a direct replacement. Not very many people carry it and the ones that do dont look like mine but say its a replacement. Any suggestions? Tried summit, jegs, autozone, kragen, and carquest.

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    Hey Nick, welcome to the forum. We have had another recent newbie come from your area recently, calling it 29Stumps. Just my .02 cents, I am not a TBI expert, so take it for what its worth. What I do know about TBI is its a rock solid durable system, until you have a warped TBI. I have been told just best to leave it alone and if it needs replaced or rebuilt, let the experts do it because they will resurface the parts to make sure there is no warpage whatsoever. So I gather you are saying the adjustable EGR is not your problem? So would it be best to clean up the old EGR valve and put that back on, and start with your troubleshooting again? This way you can eliminate the adjustable EGR as being your problem. I think you might do that, put the old ERG back on if you do not think it was your problem then look strong at your TBI unit as having possible vac leaks from warpage. Or leave the current new EGR on, start the engine up, and spray some carb cleaner or start fluid (not always a good idea) or even WD-40. Spray it around your TBI, intake runners etc looking for vacuum leaks. IF you spray this stuff, and it make the idle smooth out and raise up, there is where your vac leak is. I assume when you say looping, you actually mean loping? As in a big cam? This can also be caused by a rich setting or blocked off air like a choke being stuck. Just another thing to check, make sure you are getting good air to the TBI unit.
    85 Sierra Classic K1500
    85 Silverado K10
    84 Silverado C20

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    Senior Member Stitz Love's Avatar
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    Ah ... you can go wot and no problem. ...good sign.

    I didn't mean fuel pump had 'failed', only 'weak' based on my own '90 TBI had loping at start and wanted to stall out at stop sign/light... turned out my fuel pump was running at 5 psi instead of the target 11-15psi. (I think I have also seen target suggested as 9 - 14 psi) BUT, mine at 5 was creating those two (among several other) symptoms. Also two other members had similar issues, and their fuel pumps were registering 6-7 psi and the other 7-8 psi.
    From this I conclude that either the pumps get weaker and eventually fail entirely, or they just fail entirely at once leaving you stranded.

    But you are right, when I tried to go wot there was stuttering, hesitation and the urge to stall.

    The seasoned forum members are implicating vacuum leak... I have learned to appreciate their collective wisdom in these vehicular matters.

    Hotod has indicated the most common test, IE: the WD-40 method.
    Brad had pointed to the IAC... did you clean that while you rebuilt the throttle body?
    (Not for nothin', Brad had nailed a tranny-issue I had with his first reply... and I wasted about 4 weeks trying other stuff.)
    Has an SES or check engine light come on and gone off?
    Have you pulled any stored codes from the ALDL?
    (If so... did you post them, and I missed it?)
    1990 Chevy Cheyenne, SB (2wd / AC) with a;
    1993 5.7 from Police Cruiser (LO-5)-(?) installed by previous owner.
    (It sat for 7 years before I bought it.)

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