BoostedStroker Posted May 16, 2015 Report Share Posted May 16, 2015 Hey ya'll, i have been having a slight problem sense i have got the car but now that i am trying to dial the car in for a bigger turbo i am trying to figure out whats going on. Its a 87 Conquest with intake, exhaust, aftermarket intercooler, off brand BOV, boost gauge, shortband A/F gauge, msd coil, rebuilt motor with 18k miles, MBC and running 13 psi on the stock 12a. The car will misfire a bit at 3/4 throttle then pull just fine, it ONLY does it if i lean into the throttle and ONLY at 3/4 throttle. If i just step on it i have zero problems or stay below 3/4 throttle. It does it worse when the vehicle is cold. Here is what i have done to the car... - Replaced Vacuum advance (the one off rockauto)- Replaced spark plug wires- Replaced spark plugs with NGKs bpr7es gapped at .030 (also have the bur7ea-11's part number #7031 i have tried and it seems the car likes the bpr7es more? I can try putthing the 7031s back in?- Replaced dist. cap and rotor- Checked timing and its perfect- Checked FPR and fuel pressure and its working correctly (the nipple on the TB the fpr gets it vacuum/pressure from is not working so i have it connected to the source for the vacuum advance, i did verfiy that the fpr operates normally and it does)- Replaced ignition coil with a MSD Blaster 2 coil- Checked the TPS sensor using a scope to make sure there was no bad spots and its working correctly- Checked the MAF to make sure its working probably using a snap on verus and its working properly- According to the shortband the car is not leaning out but obviously its a shortband so not excatly very accurate. Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 19, 2015 Author Report Share Posted May 19, 2015 Also noticed intell it reaches operating temp. its worse then when its warm will even stutter/misfire if i just floor it. I am starting to think it could possibly be a injector problem? But then again when its warmed up it runs pretty darn good under full boost... Link to comment Share on other sites More sharing options...
importwarrior Posted May 20, 2015 Report Share Posted May 20, 2015 Check spark plug gap. Manual says .032 o .028 Check your cap and rotor.Make sure rotor is tight. Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 20, 2015 Author Report Share Posted May 20, 2015 Check spark plug gap. Manual says .032 o .028Check your cap and rotor.Make sure rotor is tight. I rechecked the spark plug gap and they were still at .030 so i gapped them down to .028, the cap and rotor is brand new but i will recheck them to make sure they didnt come loose. I went to pull off part of the intercooler piping to check the throttle body and noticed the clamps were fairly loose. Having a boost leak would defiantly cause my problem and after regapping the spark plugs and tighenting the clamps i could get to it seemed to help a bit because i saw the boost go up to 15 psi when it normally only hits 13 so it was defiantly leaking. Also makes sense because i could tighten the MBC to up the boost and it wouldnt go past 13 psi no matter what... Going to atleast put new clamps on all the boots and inspect the boots. Link to comment Share on other sites More sharing options...
TexasQuest Posted May 21, 2015 Report Share Posted May 21, 2015 Could possibly the pick up coil in the distributor. Link to comment Share on other sites More sharing options...
importwarrior Posted May 21, 2015 Report Share Posted May 21, 2015 i would remove the cap and make sure there is contact from the center of cap to the rotor.my cap was arcing to the rotor. once i fixed that car ran smooth.ust a thought Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 22, 2015 Author Report Share Posted May 22, 2015 Well i replaced every clamp on the intercooler, didnt solve that problem but did pick up 2 psi across the board so there was a slight boost leak... I am going to check that cap and rotor next, I just put it in not 3 months ago and ordered the most expensive cap and rotor from rock auto so it shouldn't be a quality problem. I think TEXASQUEST is onto something with the pickup coil... because it will also come close to stalling out every once in a while and it did stall out went it got really warm outside. May end up ordering one of those... for $40 its defiantly worth a shot. I mean i am running out of parts to test or check Link to comment Share on other sites More sharing options...
importwarrior Posted May 22, 2015 Report Share Posted May 22, 2015 well maybe a compression or leak down test and or a radiator pressure test?injector cleaning and flow test? Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 22, 2015 Author Report Share Posted May 22, 2015 well maybe a compression or leak down test and or a radiator pressure test?injector cleaning and flow test? I did run a compression test to verify that the motor was rebuilt (even though i could see the new gaskets on the motor) and it did really well on all 4. I would really like to take the injectors out and have them atleast cleaned and tested. If the pick up coil dosent solve the problem that will be the next step. Is trilogy the only company that sells upgraded tbi injectors? Here is a pic of the pick up coil... Rust all over so i think its defiantly time for replacement. http://i166.photobucket.com/albums/u94/okmsfootball81/0522150011.jpg Link to comment Share on other sites More sharing options...
StarquestRescue Posted May 23, 2015 Report Share Posted May 23, 2015 The vacume and pressure source for the fpr needs to be before the throttle plate. Because that is where the injectors are and there can be large pressure differences above and below the throttle plate . Perhaps you should check that your dis vacume advance / boost retard is plumbed correct as well. Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 23, 2015 Author Report Share Posted May 23, 2015 (edited) The fuel pressure regulator is NOT plumbed like it was originally. The port on the throttle plate it goes to originally is not producing any vacuum, i tried blowing air through it and its not plugged as it stalls out the engine but it does not create any vacuum so its T'eed into the source for the vacuum advance. So the vacuum/pressure source for the FPR needs to come from a source ABOVE the throttle plate? (above meaning the intake side) The vacume and pressure source for the fpr needs to be before the throttle plate. Because that is where the injectors are and there can be large pressure differences above and below the throttle plate . Perhaps you should check that your dis vacume advance / boost retard is plumbed correct as well. Edited May 23, 2015 by BoostedStroker Link to comment Share on other sites More sharing options...
StarquestRescue Posted May 23, 2015 Report Share Posted May 23, 2015 There is not supposed to be much, if any vacuum above the throttle plate. There may briefly be a little when the throttle is opened off boost . If it is not plugged you should be using that port. Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 23, 2015 Author Report Share Posted May 23, 2015 Ah gotcha, hm not sure why the PO had it like it was? just routed it back to the original spot and going to take it for a drive and see what she does There is not supposed to be much, if any vacuum above the throttle plate. There may briefly be a little when the throttle is opened off boost . If it is not plugged you should be using that port. Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 23, 2015 Author Report Share Posted May 23, 2015 After routing it the correct way, i just drove it a few miles and couldnt get it to stutter or misfire when it was warm. Ill know more after i drive it home tonight. Link to comment Share on other sites More sharing options...
importwarrior Posted May 23, 2015 Report Share Posted May 23, 2015 Thanks for the update! Link to comment Share on other sites More sharing options...
BoostedStroker Posted May 23, 2015 Author Report Share Posted May 23, 2015 No problem! hopefully it will help someone out if there having the same problem! I drove it last night (about 25 mile drive home) after i let the car warm up and it defiantly helped alot, it did it once maybe twice, but majority of the time had zero problems. I do bet my pickup coil is probably a bit worn out as it looks original, already ordered one from rock auto so when it gets here ill throw it on and see if there is any changes. Thanks for the update! Link to comment Share on other sites More sharing options...
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