4g61t.org

its probably something simple and i havent investigated very much because now it is dark and im tired

so a while back i bought this car stock 89 gt ( ) with a wasted clutch. (never driven except the ride home from purchase)
i finally got all my parts and got around to working on it. i replaced the ball joints, tie rods, cv axles, axle seals, wheel seals
and most importantly a fwd flywheel, and an act 2100 from marsbars on here

ive been working on it all week after work and finally wrapped it all up. i was so excited to actually feel the power of the car now with a new clutch. especially because i have never owned a turbo car.

but after all of the above work the car has a low rpm stumble and was undriveable this evening. as soon as i inch into the gas pedal it immediately bogs (decelerates) and the rpms go flat. i cant get it to accelerate. with the clutch depressed or at idle if i blip the pedal to full about 3-4 times i can get it to rev up past the stumble and rev all the way out but it is totally undriveable now.

any ideas?? any line in particular which causes surging stumble and being unable to rev??

im guessing i missed a connector or vac line somewhere (mainly around the aircan area above the trans).
i will investigate more tomorrow after work for sure just thought i would pick your brains.. it ran fine before all the work
it just had a very slipping clutch. it also has and has always had the lame idle surge thing but it would always rev out fine when i would take it around the block. so guessing thats unrelated

any ideas appreciated thanks

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

yeah I would check all vacume lines and more so intercooler piping/hose connections..

also is there anything for tuning? or is it all stock.




Steve

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Steve 89 colt 2.3 stroker stock top end. evo3@20 psi 13.489@99.30mph 3/10 2012
On drag radials.auto trans.launching @ 5 psi and no traction thru 2nd.

Maybe the MAF or TPS are unplugged, or a pipe off.

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"A good day racing is better than a great day fishing!"

Check all connectors to sensors, line TPS and Idle Switch. Also the coolant temperature sensor. If you can read codes do it.

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05 wrx wagon
99 Benz ML 320
91 eagle summit swapped - 6/4 bolt combo
94 Audi s4 - sold
88 Eagle Vista Turbo LX sedan, RIP

You probably have bad gas in the tank by now. Had that happen to me once after I bought a turbo car that sat for months.

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Good stuff - trucks bring it!

That's my vote.

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'18 X5
'19 M5 Comp
'07 997 Turbo, 1144WHP/1001WTQ
'17 Fiesta ST

all the tips are appreciated. i was thinking along those same lines, and its all you find on the internet when you search for those problems.

loose or missed connectors and unplugged vac lines etc. i have done those same things in the past when doing huge repairs and mostly on engine replacements. the missed line or connector usually causes rough running.

so for the update i have spent the last 2 days searching for any and all of those to no avail. i cant find a single thing i may have missed
and it really didnt unplug much to change the clutch just a few things around the air box area.

it has left me very bummed out and a little stumped.
the car still has a very exact and consistent problem where at any pedal position it will rev to 2k then bounce back to 1500 every time.
when i blip the throttle to full a bunch of times i get it to go past the 2k limit and it revs up perfectly and has tons of power under boost
it almost impossible to drive it but i blipped it a bunch and slipped the clutch to get it going but you have to keep the rpms up or it reverts back to the same problem.

now this is where it gets weird. in the back of the hatch there were some extra parts from the previous owner. headlights, center console, mass or maf sensor and an ecu etc. aside from the obvious body parts i have no idea where the parts came from or if they are even for a colt gt turbo. they are all mitsu parts tho

i tried the extra maf/mas in there and no change.
tried with the mas/maf unplugged revved up better but basically ran like crap.
then i tried the extra unknown ecu in the car and it actually ran fine at idle and revving under no load.

so i took it around the block and it ran fine but just like a N/A car
i could hear the turbo doing something but there was zero boost feeling or power.

my first thought is that maybe it was a non turbo dsm ecu that just wouldnt respond to the turbo
but it fixed the issue i was having... so maybe my ecu went bad?

i spent an hour or so googling dsm ecu part number info and found some good databases.
the ecu originally in my car is MD128615, E2t34375
from this site i determined it to be the factory 1.6 turbo ecu (http://www.4g61t.org/forum/viewtopic.php?t=9992)

the ecu from the back of my car that i tried in my car is MD153303, e2t36178
i determined it to be a galant gsx. how rare is that? its a non turbo 4g63 galant like vr-4 but non turbo
found info from (http://simon.chi.il.us/ECU/ECUID.html).

so in conclusion maybe my factory ecu is causing the weird inability to rev and the non turbo ecu i tried solved the issue
but wouldnt manage the turbo explaining the lack of turbo feel? i dont know its all kinda weird and i have had to much beer to
drink now to consider all the variables

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

Do you have anyone you know with a logger or scan tool who can look at the ECU with engine running? Take the cover off your ECU and see if there is any corrosion or damage from leaking caps etc. Check out this page for info on what to look for it you're not familiar. http://www.ecmtuning.com/wiki/ecurepairhome I wish I was a little closer, I'd come take a look.

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'89 Colt GT w/bigger than stock turbo
'91 Talon AWD w/bigger than stock turbo
'05 Dodge diesel w/bigger than stock turbo

update

aside from checking everything over again i have found nothing i missed or didnt plug in.

from craigslst i purchased a supposedly working 90 dsm turbo ecu and tried that I verified it was a 90 ecu from the ecu id database. the car did flat nothing...turned over great but nothing no sputter no firing nothing. assuming the ecu i bought is no good. (seller was very cool and should take it back).

put the original one back in for fun and had the same problem of not revving past 2k just surging from 2k to 1500. No surprise there

and also for fun i tried the galant gsx ecu again(non turbo ecu from the parts found in the hatch) and it ran like total crap this time barely ran. bad idle and bad throttle response. weird because it actually worked the first time around just ran like an N/A car but revved up normally.

its really a bummer i dont know anyone with any dsms so i could actually swap back and forth with known working parts to remove some variables.

im pretty much just stumped. from purchase i drove the car 4 hours home and it worked fine boosted and everything just had a bad clutch
fixed the clutch and some other things and now it doesnt work....really points to me overlooking something or damaging something in the process of fixing the car. but i dont know what

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

It doesn't sound like you are actually testing anything. I can fix it for you in one afternoon, but you would have to get it shipped to Dayo's Garage 15 Fillmore Ave. Tonawanda NY 14150. See you soon.

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"A good day racing is better than a great day fishing!"

update
^^i wish i could ship my car to new york and have you fix it!! ^^

ok still trying to figure out why my car wont rev.
the ecus were a wild goose chase and the ecu works fine.

i finally figured out how to get the tmo datalogger working on my car thinking that would be a good tool.
It stretched my brain a bit with building the right cable and finally figuring out to change the com ports
it actually all works though and it connected

this is my first time with anything like this and i realize there is a lot to learn with the logger
(what an awesome tool though)

i did one quick log after it warmed up and the only interpretation i can make is that
it proves the problem where i hold throttle at 11 percent (enough to get it to rev to 2k) and then the
rpm oscillates between 1500 and about 1900 up and down as long as i hold the pedal down above idle.
airflow and injector pulse seem to go up an down right with the rpm even though i am holding constant pedal position
the more throttle i give it it shows an increase in tps on the logger but no difference in the oscillating idle

Are there any values i should be looking for?
all help and info is very very appreciated

here is a pic

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

wow i finally fixed it!! this thread is over

the datalogger helped me but in a different way.
it showed me the details of the ecu under the ecu info tab and it verified that both my ecus
were 91-94 style even the one i recently bought specifically as a 90 style.

so i searched around about using 91-94 style ecus in a 90 car
switched the two wires pin 6 and 14.

it worked like a charm and i spent an hour driving it around last night. its all stock and now runs like a champ. it is a fun car. only took about 8 months of it sitting dead lol

here is a pic of how it looks now with some new to me wheels off craigslist and new tires

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

Nice car, glad you got the issue worked out

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89 Mirage Billet 20g 63t 12.4@120 417whp 400wtq @ English Racing.
89 Colt GT E316g
06 Silverado SS
07 ZX6R