OK if you don't know i have an lt1/t56. The problem keeps coming back and i have no clue what the hell it is. First i was told i had a batch of bad gas! so i burned it all out and i mean BURNT..lol i never got on the fc this hard before in my life! I let the temp get up to 210 and then beat on it. and the problem went away. I took the car out for a nice day out with the wife and i filled up with 93 from shell. drove fine the whole day. we went shopping had dinner went to a movie no problems.

Now its evening and its a lot cooler and then the motor started doing it again! Bucking and jerking like it wants to go but nothing. Now here is what i am thinking and what i was told by some vette owners. The problem seems to only happen on cooler times, like in the high 50's to low 60's. If its hot out and the temp stays above 180 it doesn't do it. When its cooler out and the car is closer to 160 it does it a lot. So i was told that i am running the motor way to cool. So today i am picking up a 180 instead of the 160 that i have in it now.

One vette owner told me "its your TPS" now this is coming from a guy who owns an 88 vette and says "yeah we have the same motor mine is an lt1" when you go and look at it its a TPI motor. I asked another vette owner how has a 93 vette and he is the one who told me about my temp being to cool for the motor that likes to run hot.

What do you guys think? I ran my codes via my pc and data cable and the only codes i have are one for the auto tranny. So i need your help its pissing me off and i have no clue what else to do. I was wondering if it was my MAF or air temp sensor? again it only does it when i step on the gas, and when the motor is cool. i can go home right now and start it up and it will start fine. i let it warm up to 160 and i don't notice it but if i step on it hard it seems like it is doing it. PLEASE HELP ME !!

 

Well, to begin with apparently it has always done this, so trying to analyze it from the stand point of an onset/ beginning time is moot. You are doing the correct thing by searching the sites, both Lt1 and Vette. Usually a na engine runs better when it is cool----certainly puzzling. How about your plugs---are they in good condition, the correct ones, including gap and heat range? I.e, you aren't running any wierd ones are you? Good luck.

 

well it never did this to me. i have had my motor in my rx7 now for almost 2 years now. and never did it do this to me. As for the plugs i bought them 2 years ago and i don't even have 5000 miles on them yet. as for wires i have taylor wires. my fuel pump is a walbro 255, my fuel filter is a summit racing filter. all of this with less then 5000 miles. to be exact 48xx miles on it. the motor has 58,xxx right now since the swap. the opti spark is also included in this along with the coil. I do have an extra opti spark that came with the motor but i swapped it out because i didn't want to run into a problem down the line. the coil i just figured i change it while i was there also. i was thinking about changing the plugs as well but man i can't see 5000 miles in 2 years hurting me. and it all started after getting some gas out of state. i am so lost right now!

 

If you can datalog with a laptop do that and post it here and i'll give it a look. Otherwise if its a sensor issue its gonna be a little tough to track down until it totally fails. While I was at it I would verify fuel pressure and try to get it to show the symptom with the gauge attached.

 

How about your sensors---are they telling the PCM to add fuel because the air is cooler, but not as cool as the sensors are telling it therefore overly rich condition? I'd check at least one plug to see if there is some indication of overly rich mixture and go from there. I trust someone else will provide a better possibility.JMHO

 

yeah i bought a fuel pressure tester just for this motor i will test it as soon as i get home! any other kind of software i can download to check my pcm? i have tuner cat and data master but for some reason data master doesn't seem to work to good for me

 

o and would you rule out my opti spark? or is that still in play?

 

No I wouldnt rule out ignition or opti spark. I just tend to look to fuel or sensors first.

Download freescan if you can't get datamaster to work. Its just easier to see problems on data master with the graphs and all.

 

ok tested the fuel as soon as i got him and was at 0 with the key off turn the key to on shot up to 42 turned the motor over and it fell to 38 during start up and then stayed at 41 reved it up and it went to 44ish range but it never fell below 41 i drove it around the block and it stayed between 41 and 44 never dropping below 41. i downloaded freescan and the only code it is reading is "16 Jun 08 18:00:24 - 0x92 0x55 0x19
P: a6 - Unrecognised header
P: 05 - Unrecognised header"
but i am not sure if it is reading right because i turned the motor over to see if all the readings would read and nothing at all. it shows me no trouble codes or anything.

 

ok i was playing around with it and i found the trouble codes here is what i have:
82 shift a solenoid fault
83 tcc control feedback faul
84 3-2 downshift feedback fault
11 malf indicator lamp (mil) fault
code 77 fan 1 fault
code 78 fan 2 faul
code 14 coolant temp high

now for code 82 83 84 those are all auto tranny codes right? if so i will take those off with tuner cat. now code 77 and 78 is because i am manualy controling my fan inside the car
now for code 11 and code 14 i have no clue how to fix those codes. can anyone give me a hand?

 

Since you have a T56 (the code definitions you quoted are for a 4L60E), 82 is not a valid code, 83 is for the reverse lockout solenoid, and 84 is for the skip shift solenoid. Do you have the solenoids hooked up still? If so, did you check the fuse, because they are on the same fuse as several engine sensors.

Or was your PCM originally programmed for the A4, and not reprogrammed to an M6?

 

my pcm is for an A4 my auto tranny was a pain in the butt. so i changed it to a t56. but i still don't don't know how clean code 14!

 

DTC 14 means the coolant temp sensor (the one in the water pump housing) voltage is too low, indicating an unrealistically high coolant temp (266*F). The sensor is internally shorted, or the sensor wiring is shorted to ground. Shoebox has a table showing the spec's for resistance of the temp sensor vs. the coolant temp.

http://shbox.com/1/4th_gen_tech2.html#ect

DTC 11 indicates the SES bulb is burned out, the wire was cut, or you didn't hook that circuit up when you transplanted the PCM to the RX7.

 

so do you think that this temp sensor is sending a false reading to the pcm and is why its acting this way? i cleared the codes lastnight andi started it up and it still did the same thing. i am taking off my fuel filter today and going to take it to autozone and see if they have a replacement filter for me. only because mine has AN fittings on it.

 

As Injuneer pointed out, I would check the water temp sensor on the water pump. I had similar symptoms on a '95 Corvette and the wiring to the water temp sensor was eroding away at the connector. A look with a flashlight and everything looked good but when I disconnected the plug to inspect the terminals the wiring was rather frail and intermittant. I changed the sensor and the connector plug (ordered from GM dealer) and that cleared everything up. I believe the intermittant connection would cause the water temp reading to the PCM to fluctuate. Therefore the PCM would jump from table to table attempting to apply the correct parameters for that temperature and load.

Later ... Larry S.