87 tona, wont rev past 4500, now is dead.

[TurboDoctah]

Quote:

Originally Posted by tryingbe What about driving in gear?

Only drove it once since i havent gotten the title switch/plates yet. it does fine just crewzing but i didnt bother to try to take it past 4500 thats where i shifted cuz it was bogging down at 10psi @4500r's i did floor it a couple times to see what would happen. it was slow as hell lol. felt Okay at 5psi lower rpm's but the higher it went in the r's the less power it had. and my roomy was tailing me he said it was huffing black when id punch it. my eyes and nose was burning quite bad by the time i got home (3.8mile drive) since the waste gate is vented.

[91CSdaytona2.5]

I'll be curious to see if you ever figure this one out.... My '91 is doing the same exact thing!!! Sounds like it starts dropping 1 or 2 cylinders (misfires) at ~4,000 rmp then around 4,500 it falls flat on it's face... driving or sitting still makes no difference. Runs flawless up to that point, smooth pulls good, no stumble, starts/idles great.
I've checked fuel pressure (steady ~55psi and climbs some during boost), checked base timing at 12 degrees w/ temp sensor unplugged, checked cam timing (newer belt), SMEC throwing codes of 12, 22, and 55.

I was suspect if it was ever going closed loop since my mileage has really gone in the toilet (Used to run ~30mpg hwy, but now can barely do ~19mpg)
I see the timing fluctuating slightly so I'm assuming that's not the case?
Coolant temps ~190 degrees.
I'm stumped! It's almost like it hits an overboost condition, but it's barely making any boost when rev'd/parked.

I'm assuming it's brain dead. This is a Mopar Performance SMEC and I really don't want to fork out more $$ for another one.

Any other ideas would be much appreciated.... even wild guesses at this point.

-Greg

[TurboDoctah]

Yep. pretty close to whats happening on mine... but i swaped in a stage 5 ecu.. same thing... i just put in new plugs.. noticed that #4 was clean almost like new.. 1 2 and 3 looked normal... after i put the new plugs in i took it for a spin.. i hit 21psi (not doing that again, cranked the boost all teh way down now lol) checked the new plugs.. 1 2 and 3 look normal... 4 is perfectly clean.. im guessing #4 injector is dead or cloged.. it Ran perfect for a sec.. ssounded just like my roomys t1... then it went back to its drag car sound.. now that i think about it i have a shut off for one injector on my neon (attempt at better mpg) and it ran/sounded just the same.. so #4 isnt doing a damn thing... not only am i gonna rip out the injectors and clean them/test them if i can.. imma replace the ballast for the coil cuz it has an odd problem of stalling and Not starting up again.. but if i turn teh key off wait 30 secs and crank it again it fires up again... odd.. also when i was getting it unstuck from all the snow in my driveway it was shooting flames out the tail pipe.. and at idle right b4 it died ideling b4 i took it on the road it was spitting out sparks out the muffler and popping... i was just told by a old dude who knows his shizzle that theres a group of 3 wires that goes to the battery that oftian go bad and cause the thing to die like its doing... but i havent found that group yet cuz the batterys in the pass side floor board lol. so imma have to hunt for them. im also gonna test for 12 volts at the coil and 12v at the injector thats not working. and thats all i can say for now.

[Dis' Trot]

Bad computer. They go bad. I had one crap on me tried 3 till i found the one i liked, these are old cars. Your best off buying one from FWD preformance, new parts and they trick it out for you.

[TurboDoctah]

Quote:

Originally Posted by Dis' Trot Bad computer. They go bad. I had one crap on me tried 3 till i found the one i liked, these are old cars. Your best off buying one from FWD preformance, new parts and they trick it out for you.

the one i just put in is a forward motion stage 5 or fwd preformance not quite sure but its new enough. wouldnt explain why 2 do the same thing. im Highly doubting the ecu's are bad.

[turbokid]

Damn you have yourself an issue... Hmm when you unplug the map did it run crappier and then catch itself??? Is it bucking at all until 4,500 rpm. If you just let it sit and idle will it just idle the whole time??? does it die eventually with no revving???

[TurboDoctah]

Quote:

Originally Posted by turbokid Damn you have yourself an issue... Hmm when you unplug the map did it run crappier and then catch itself??? Is it bucking at all until 4,500 rpm. If you just let it sit and idle will it just idle the whole time??? does it die eventually with no revving???

well i have only let it idle maybe 3 times and 2 outta the 3 it died after a while.. i havent tried unpluging the map yet. it runs with out bucking when i drive it it just has no power at all.

[91CSdaytona2.5]

Quote:

Originally Posted by Dis' Trot Bad computer. They go bad. I had one crap on me tried 3 till i found the one i liked, these are old cars. Your best off buying one from FWD preformance, new parts and they trick it out for you.

That's what I'm thinking too... My ECU is only about 7 years old, but guess they don't last forever....

I haven't tried to unplug the MAP as it runs flawless up to the 4,500 mark.

TDoc, I've wondered about the injector issue, but why does it work great up to that rpm? Seems electrical versus a flow issue... I would think it would throw a code for misfire injectors, but nada/zip/zilch...

My first ECU was throwing injector codes when it died...

Not sure why the ECU you tried wouldn't help... makes me even more confused

[TurboDoctah]

Quote:

Originally Posted by 91CSdaytona2.5 TDoc, I've wondered about the injector issue, but why does it work great up to that rpm? Seems electrical versus a flow issue... I would think it would throw a code for misfire injectors, but nada/zip/zilch... My first ECU was throwing injector codes when it died... Not sure why the ECU you tried wouldn't help... makes me even more confused

i have owned quite a few cars that dont throw any codes but a part is bad or its missing or what ever the case may be... the ecu aint as smart as it should be lol.. i have No codes as of yet.. i was just about to take it for another test drive but low pro's dont do snot in the snow and i got stuck so i had to abort. i tapped the "bad injector" and the car ran better for a min or 2... its to late now for me to mess with it any more i woke up the ppl next door when i got stuck lol waiting on the pigs to show up now lol.

[TurboDoctah]

Would a bad TPS prevent me from reving past 4500? i knwo if you unplug it you cant get past 3500 or so.... its just an idea. Also what is this computer for?

[FFWD]

The only time I had something like that happen, my cam timing was off. I think a tooth retarded. Check that.

[TurboDoctah]

i gave up. lol. theres a little shop around here that has pretty much nothing but turbo cars that they fix... so i took it there. i am to afrade of blowing this thing up before i figure out whats wrong with it(since i didnt build it so i dont know ever detail on whats been done.). lucky for me the ecu threw a code as i was driveing it there... plus most of the ppl there have owned turbo dodges so they should be able to figure it out. ill take the loss to prevent me from blowing this thing up. iv already hit 21psi (on a t3/t4 with a pre cb)atleast 4 times not knowing what the fuels doing. i did turn it down to 10psi once i figured out the boost controllor (its backasswards from normal boost controlers.) now i didnt hear Any signs of detination.. so im sure im good there. but i figured id stop where i was cuz iv been beating teh piss outta it trying to figure it out. ill let you guys know what the problem was and how it was fixed when i get it back IF they can fix it.

-Bob.

[91CSdaytona2.5]

Quote:

Originally Posted by FFWD The only time I had something like that happen, my cam timing was off. I think a tooth retarded. Check that.

I've thought that too... Timing light shows the hole in the pulley right where it's supposed to be. I'm heading out to pull all the shrouds/pulleys and verify the marks again (I'm paranoid as I know it's got to be something simple)

I've put a new TPS on not long ago... if disconnecting the TPS will not allow revs >3,500... I would assume a bad unit would yield similar results.

Anybody need any good parts? I'm about ready to part out

[Lone Eagle]

Quote:

Originally Posted by TurboDoctah Would a bad TPS prevent me from reving past 4500? i knwo if you unplug it you cant get past 3500 or so.... its just an idea. Also what is this computer for?

That is an SMEC(Single Module Engine Controller), and is used only on the '88/'89 models. The SBEC(Single Board Engine Controller) was introduced in 1990, and only has the 60-way connector. They WILL NOT interchange, as the white connector is for the injector driver/control circuit, which was integrated into the mainboard in 1990.

[TurboDoctah]

Quote:

Originally Posted by Lone Eagle That is an SMEC(Single Module Engine Controller), and is used only on the '88/'89 models. The SBEC(Single Board Engine Controller) was introduced in 1990, and only has the 60-way connector. They WILL NOT interchange, as the white connector is for the injector driver/control circuit, which was integrated into the mainboard in 1990.

Hmmmmmmmm, well i have the dual connector one on my 87. and one of the connectors was replaced as all the wires was cut and have tape on them now.... wundering if that would of caused a problem with an injector not fireing.