serious help needed please!

[endonesia]

i just don't know where to start. 86gn car bucks and pops, sometimes under boost, sometimes just by tip in, sometimes in park by revving. using snap-on scanner and vantage, movie mode shows tps dropping out just before cutting out. also fuel pressure set at 43# drops as low as 25# after warming up. SES light flashes when cutting out, but does not show code. i have no digital dash, no radio, no power on brown wire for alternator(using 85 w/self exciting regulator), and also showing code 24(vss).

car has new:
-340 walbro, racetronix hotwire
-accufab regulator
-fuel filter
-tps
-02 sensor
-cam sensor
-crank sensor
-wiring harness, used but checked
-2 ignition modules
-2 coil packs
-plug wires w/autolite 24 gapped .35
-alternator(can't use yet)
-battery w/new cables
-ecu

came with:
-3.5" maf w/translator
-extender chip
-exhaust w/no cat
-adj. wastegate rod

i've checked & cleaned grounds on fender and head, adding strap from firewall to engine. checked starter wires by header. digital dash flashes on sometimes when severe popping happens, but only then. fuses all ok. was showing code 42(est) with new module, went away w/old module.

i feel like i've read every archive post on this helpful board and others, but am out of resources and ideas. i love turbo regals, and got a good deal on this one because it didn't run and was really hacked by "mechanics" almost everywhere. i have fixed a lot of the bugs, but could really use some TR guru advice on what to check next. thks.

josh

 

[azgn]

reseat your chip and reset the computer, see if that helps....if that doesn't work, swap out the ecm with a good one

 

[endonesia]

tried that, have backup ecu. also have stock chip, kenne-bell chip, and have reseated chip multiple times. i wish it could be that easy. thks.

josh

 

[ES1]

Does FP go up as RPMs increase?

 

[endonesia]

yes, but at about 5#'s of boost it starts cutting out and popping so revs drop. that's when tps goes to .42, then 4.7.

 

[Reaper]

so it misses all over the board huh? coil pack! get a known good one and test it. your plugs are a bit hot also, try 23s if you stuck on autolites. or cr43ts in delco. try that and see if it helps.

 

[endonesia]

forgot i changed to autolite 23s a couple of days ago. i have tried 3 coilpacks so far 2 of them out of the box new. i think my other problems(dash, radio, alt. wire, vss) are all somehow related, hoping somebody will see something i don't. thks.

josh

 

[azgn]

no doubt you have looked at all the fuses, checked the battery, checked the "alt" idiot lite bulb (you have that on a dig dash car?)

if the alt isn't charging a low voltage prob "could" cause your probs?

if the idiot lite is out, no charge........

 

[IrvJr]

I had a problem like that and it turned out my battery was bad. It tested good on the car, but i took it out and had it tested out of the car it was bad with lower than normal voltage. Maybe that will help you, it did wonders for me.

Scott

 

[endonesia]

that's my whole point, i have no + at bulb for volts, hence no + at brown wire. that's why i'm running 85 alt. with self-exciting regulator. i switched in brand new alt. sunday, left me stranded at gas station because i took 85 alt. off and wasn't aware i wasn't charging.

when i first got the car running volts light did work and it was flickering. i have an 85 engine from previous gn laying around so i threw it's alt. on. ran it like that chasing these problems, decided maybe problem lay in amperage difference(85 is 90amp 86 120amp) switched new alt. realized no + at brown wire too late after it was already dead. thks.

josh

 

[endonesia]

have had 2 brand new batteries in it so far. no difference. thks.

josh

 

[humberto]

Is it possible that you could have a pinched wire somewhere like maybe between transmission houseing and block?Or maybe a burnt or melted wire?I cant think of anything else?You have tried just about everything?Are all the connections at the ecm ok nice and tight?Maybe try pulling on diff parts of harnesses to see if car stumbles?Good luck.

 

[ES1]

Try replacing battery cables? Bad connection at the computer? Might email John Spina at Caspers Electronics.

 

[gn1090ss]

hey endo:i have owned at least 1 of these cars since 1990 and your problem reminds me of my 1st gn in 1990.car had same problems as yours except I didnt have a fuel press. tester. After much repair shops excursions it was found that the cars cam sensor was set wrong by the previous owner as a cam and headers was put on the car.your problem sounds like the fits I had with this car..........

 

[endonesia]

gn1090ss, weird you called me endo...thought maybe you knew me...you reminded me that this car had a crane cam in it at one point which came w/car not installed. turns out the cam sensor was 180* out. fixing this helped out a lot, but i am still having fuel pressure problems.

when i first started it after fixing cam sensor, i had about 33 psi at idle and she roasted tire up to about 14-15# boost, then cut out. kept on driving, and fuel pressure went down to about 24 psi, dipping as low as 18 psi once. when this happened i was starting to cut out again as low as 5# boost, but it was better. fuel pressure rises w/boost but idle psi is about 10 psi low after about 5 min. of driving.

got home, put on lift still running, checked voltage at fuel pump and was getting 13.3-13.5v. fuel pressure still sitting at about 24 psi. turned off, rail held about 27 psi. turn key on, rises to 37 psi then falls suddenly to 27 psi again. SES still flashes when cutting out with no code. andybody have ideas?

josh

 

[gn1090ss]

does your fuel pump make any noise?????even if it doesnt id say that your vanes inside that walboro have failed ...........drop tank and check for metal shavings in tank.however that might be only part of the prob. since your pressure drops at the rail with key ON and car not running........maybe also injectors.Does your oil smell gassy or does it turn dark fast??????hope this helps

 

[endonesia]

yes, walbro makes very slight whine, but has since i put it on and that wasn't even a month ago. car has probably been driven less than 400mi. since i got it running, maybe 100mi. w/walbro. i changed the injectors 2 days ago to the ones off my old 85 engine laying around(by no means new but the fuel pressure drops same way the 86s were), because i suspected them as part of the problem.

fuel pressure is great if engine is cold-about 37psi but as soon as i start driving it dips into the 20's, i just don't get it. the only thing i can think of is when i replaced fuel filter, nasty rusted crap came running out of the clogged old filter. maybe some of this crap is still in tank or lines before filter? maybe new filter is already clogged? i will drop tank again, check pump, and inspect lines. thks and keep suggestions coming, cause i'm out of them!

 

[Mustang 1]

Hello! It sounds like a similiar problem as me! I have chased this problem for ever, about three weeks now; and lost lots of sleep in the process! I replaced a Walbro 307 with a 340. I replaced an Accubfab billet fuel pressure regulator with a new billet regulator from PTE. The car also has new injectors and a new fuel filter. Also every fuel iline is new. I still have the same problem! I to was suspecting the alternator and the problem is not it! Guess what? The fuel pressure gauge is rail mounted and glycerin filled. It is also about 2 years old. After doing all this work on Saturday the fuel pressure dropped like 20psi after driving and I adjusted the fuel pressure up twice on the way home! What clued me in was the more that I turned up the fuel pressure the worse the car ran! Also, I turned the fuel pressure down to an indicated 0 psi; and the car still ran! Also, on Sunday morning, the fuel pressure was an indicated 80 psi! This is the max rating on the Walbro 340! I just got my new external fuel pressure gauge that I will mount on the windshield tonight. I feel certain that will fix atleast this issue! You might check yours!

 

[endonesia]

i am confused. do you mean you have problems with fuel pressure gauge, or your car is cutting out? i have been using digital gauge in car until i severed the line in the hinge, now using snap-on mechanical gauge taped on windshield. i'm not sure i understand what your problem was and what fixed it. thks.

josh

 

[Mustang 1]

Both.The gauge was indicating much lower fuel pressure than was actually there and the car was cutting out because it was overfueling.Too much fuel .... 80psi.....way too rich!