car ran great now no 3/4 to WOT

8

86 got boost

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Joined
Mar 17, 2005
86 GN... I just replaced fuel pump w/ new walbro pump w/ hot wire and a new GM sender. RAn great..., then no 3/4 to WOT
Fuel pressure at the time it's happening is 60psi w/ no flutter of the needle or drop pressure, idles at 42psi ... car pulls hard but 3/4 throttle up to WO its like you took your foot out of it, shut the car off, and the waste is being let go at the time, If you let out the throttle and then back on...
pulls then bogs (unless at half throttle down is ok)....
Im running big stuff 3 also, no changes and all looks to be ok/ same since pump change?...
Any suggestions, give me some idea's...
__________________
 
If everything worked fine before then go over everything you just changed and make sure all is wired correctly.
 
took her out and did some records, just dont understand she coughed twice, Im at 18 to 20 psi boost rpm at 5250 and throttle at 93% and dont see anything out of the ordinary..
 
tuning I have done, have not changed anything, also tried several other files all run the same... all happen at the same time... how bout air in fuel lines, heard about the hose that replaces the sensor on sender, could come loose...? might switch out the TPS, It seems to sweep with glitching but thats looking through the big stuff 3, (TPS) can I ohm and check for opens? Tps set 2.0% at idle so its set right?
 
car ran stronger after, this is new gremlin that just hitched a ride... did check over all besides in the tank... she runs great otherwise idle, cruise, just when she opens up... even checked my piping for IC nothing???
 
tps

It does sound like you have a tps issue but only time will tell . Do you have a scan tool where you can see the tps volts ?? If I remember correctly it should be at 0.42-44 at idle and 4.6 to 4.8 full throtle and I am sure others will chime in.:D
 
tps

I would say put a volt meter on two of the tps wires, (dont remember which ones) then turn the key on , dont start the car and slowly twist the throttle open with your hand, check to see if the voltage drops out to zero or anything like that should go up the whole time the throttle position increases, up to 4.7 or so volts i think. I think the tps is on a five volt system...
 
also check the boost hoses in between turbo and throttle body

boosted connections between turbo and throttle body, not sure if you had any of these off or if one worked it way loose, it could blow off then suck back up, seen this on a different kind of car/motor in 2 different instances, they were mustangs with front mounts and 1 with turbo, 1 with blower... just another thought.
 
mine did the same thing it would run perfect till 3/4 then if i hit it down it would just fall over and die until i let off the gas a little then it would come to life. i never figures it out. i to changed the pump and gastank
 
IC hoses?, yes I yanked to see if they came loose, there tight... Its driving me crazy
she falls on her face, then next run she's coming out of her skin fast, then try again, a couple hick ups, never any knock makes me think, does it even work besides when I start the car up? checked all the vacuum hoses also, had a pinched fuel regulator vacuum line, could barely blow through, fixed that, same thing going on...
 
I have had that problem twice, once it was the crank sensor. The other time the battery cable was shorting on the passenger header on WOT, that was tough to find.
 
yes but not sure how to post, have 30 sec. of real time I recorded, but writing down , not going to show real feed.. just pulled IC tubes, checked out throttlebody, all clean no oil or carbon build up, anyway to check the ignition module? replaced coils recently cause of corrosion.. how bout cam sensor? been there since I owned, 10 yrs.
 
and thanks to all for the replies!!... help goes along way when your stumped, keep'm coming if any more idea's....... even if there's someone close to check out my computer would be appreciated will take the ride no prob. there...
 
had a similar issue with my car. took the plugs out and they were gapped way to big. changed the plugs and it fixed my problem. Im sure you already checked that but that was my issue. good luck man
 
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