Jump to content

3.4l stalls at wot and check engine light comes on


dodgeman

Recommended Posts

this just started today. first, the car has 60000 miles on it. i have already replaced the intake gaskets, fixed all vaccum leaks. this week i have put in a ub3 and wired it up. everything seemed great. i got the tach to work yesterday, everything seemed ok, although i did not do a wot yesterday. today, i replaced the oil sending switch with the correct one for the ub3 and had the oil changed, after that i filled my tank with gas. when i stomp it it bucks and sounds like it is starving for gas and then the check engine light comes on. If i accelerate normally it seems to be fine and if i hit the gas to downshift it is ok, but if i go to downshift and go all the way to the floor then that is when it starts to buck. any ideas? thanks

 

Link to comment
Share on other sites

  • Replies 56
  • Created
  • Last Reply

Top Posters In This Topic

  • dodgeman

    27

  • RobertISaar

    15

  • tornado_735

    6

  • spiderw31

    2

well, i went back out to the car to drive it again and this is my diagnosis. If i am above 40mph and wot it is fine, it kicks down a gear and gains speed. if i am below 40, around 35 and wot, then it kicks all the way to 1st and starts bucking, plus i noticed the tach bounces to the 7000 like i have hit the red line limiter or something. this digital dash has me redlining at 5500, and i thought the 94 3.4 relined at 6 or 6500.

Link to comment
Share on other sites

I know this dont make any sense but i am going to remove my ub3 and see if the conditions are the same. That and adding a real oil pressure switch are the only things i have done to it. my mechanic closes at 4:30 everyday and i work till 4:30 so i cant get over to him until thursday but i can take the ub3 out in 10 min after work.

Link to comment
Share on other sites

well, i went back out to the car to drive it again and this is my diagnosis. If i am above 40mph and wot it is fine, it kicks down a gear and gains speed. if i am below 40, around 35 and wot, then it kicks all the way to 1st and starts bucking, plus i noticed the tach bounces to the 7000 like i have hit the red line limiter or something. this digital dash has me redlining at 5500, and i thought the 94 3.4 relined at 6 or 6500.

 

Interesting... I had a 6000LE with the 3 speed that would just bounce the rev limiter instead of upshifting, and would sometimes try to downshift to 2nd at 80mph. I just learned to let off the throttle at the proper times to let it upshift! :lol:

 

But that was a non-electronic tranny, and I digress. Not an expert on the clusters, but it sounds odd that it could cause that sort of issue. If the car was fine just before the install, and that really was the only change made, pulling the cluster is a solid way to start troubleshooting.

Link to comment
Share on other sites

I've had TH125C's do that too, actually I've had older 4T60's (non-electronic) tranny's fail to shift at WOT unless the throttle is lifted slightly.

 

Never had the misfire accompany it though... that's a stumper. The only thing I can think of is that it sounds like you're hitting the rev limiter.

Link to comment
Share on other sites

if it were the coils would the car seem to run normal? idle normal? and run and drive normal unless i kick it down into 1st gear and wot? i am not a mechanic but i am sure learning alot from you guys

Link to comment
Share on other sites

No coils would usually fail under high-load situations more than high-rpm ones. Does the check engine light go out as soon as you lift out of WOT?

 

OBD1 is such a pain to diagnose...

Link to comment
Share on other sites

Did you have this stumbling situation before you got into the repairs you've done or has this shown up afterwards?......the redline for the DOHC is 7 grand but the ECM limiter comes in at approx 6200.

Link to comment
Share on other sites

the check engine light is out the next time i start the car. this did not start happening until i started doing these changes. the only other thing that happened was here in florida on thursday and friday we had a lot of rain and i had to drive through alot of standing water many different times. can i do the paper clip thing on a 94, and if so is it just jumping the orange and black one next to it or how?

Link to comment
Share on other sites

the check engine light is out the next time i start the car. this did not start happening until i started doing these changes. the only other thing that happened was here in florida on thursday and friday we had a lot of rain and i had to drive through alot of standing water many different times. can i do the paper clip thing on a 94, and if so is it just jumping the orange and black one next to it or how?

 

Oh, not on a 94. I someone said it was OBD1. No, you can't do it to ODB1.5.

 

 

Link to comment
Share on other sites

well, it is the ub3. i unhooked it and it ran fine. then i removed the orange tach wire, hooked it back up and still ran that way. so i double checked all of my wires and they are hooked correctly for the pin outs that i have. I have the pin out of the base cluster and ub3 cluster. I know the base pinout is for the basic digital dash and i have analog. Some where on here i found another pin out that was very close to mine but still had wires not being used that were being used in my plug. So basically, all of the wires are matched by color code with some of the ub3 wires left over and some of the ones on my plug left over. I dont know what to do now. I guess i could leave it hooked up and have the code pulled, maybe that would lead me to the right wire. Does anyone have a completely accurate pinout of the 94.

Link to comment
Share on other sites

i made some phone calls to the dealers in the area and on service tech said it sounds like the vss on my transmission. since my analog redlined at 6500 and this digital redlines at 5500. he said it sounds like the cluster sees me hitting redline. he said i could put a vss from a 91 on there and that should fix my problem. any thoughts on that one?

Link to comment
Share on other sites

He has no idea what he's talking about.

 

holy hell, this CANNOT be repeated enough... apparently guage clusters are also rev limiters :willynilly: :willynilly: :willynilly: :willynilly: :willynilly: :willynilly: :willynilly:

 

OBD1 is such a pain to diagnose...

 

true, but it makes you MUCH better at actual diagnosis instead of relying on electronic gizmos...

Link to comment
Share on other sites

there are so many different answers in here about the rpm reading that i dont know what to believe. I know that my analog redlined at 6500. I know that this ub3 redlines at 5500. Some say my aldl will tell the guage what to read. some say it wont. others in here have the same year car as me and their ub3 says 5500, others say 6500, I found out today that the 1991 cutlass had a 3 speed and a 4 speed, were all 3.1l 3speed? were all 3.4l 4 speed? my cluster came from a 1991 with the 3.4. does anyone know if the ub3 was just maybe different for a 3 speed or a 4 speed. I also know that the VSS for the 1991 had 2 different part numbers, one for a 3 speed and one for a 4 speed, so maybe the cluster i have is made for a 1991 with a 3 speed and a redline of 5500. I havent heard anyone say anything about all of the ub3's being exactly the same. Are they? maybe the redline is determined by the ub3, maybe they did make different ones for a 3 speed or a 4 speed. I dont know, but i dont want to be made fun of for not knowing everything about my car. that is what this forum is for. I have questions that i dont know the answer to, and wastes my time to see that i have replies to this post and here i am thinking......someone has an answer for me, just to find 2 of the posts were useless. If you are going to say that this guy dont know what he is talking about, dont just say that and leave. obviously if you know he is wrong, then give me the correct answer, that is no different than telling your kids not to do somehthing......"just because i said so". so if you have comments that dont help me then please dont waste my time and yours by making them

Link to comment
Share on other sites

If you are going to say that this guy dont know what he is talking about, dont just say that and leave. obviously if you know he is wrong, then give me the correct answer, that is no different than telling your kids not to do somehthing......"just because i said so".

 

being 1 of 2 posters, i'll say this: the dash has NOTHING to do with the rev limit, that's something that's handled internally by the ECM. when IT thinks you've gone too far, it will step in.

 

as far as your analog dash saying 6500, that sounds roughly correct. however, the digi-dash SHOULD be more accurate, since the reliability/accuracy of the analog guage is taken out of the equation. find someone with a scanner or laptop with an ALDL cable and record what's happening. if it really does think you've hit the rev limit, the ECM will command a 0ms pulse width until the RPMs get under the re-activation threshold.

Link to comment
Share on other sites

sorry about the rant and i was not referring to you. I am off on thursday and i will get my mechanic to pull the codes and we will go from there. I may pull the vss wire off after work tomorrow just to see if it still happens. I am pulling my hair out.

Link to comment
Share on other sites

took it everywhere but to a dealer and noone had the scanner to pull the codes and i didnt want to pay the dealer fee right at this moment. so i took the cluster out again and checked all the wires. my mechanic gave me a print out of my cluster, but it did not have any of the idiot light hookups, just the main connections. all of those seemed to be right and the same as what i already had. I removed the vss wire, it ran the same way, removed the oil pressure wire, ran the same. i am still at a loss. i dont understand how a cluster (which is reads inputs only) can cause this, unless there is a wire crossed up somewhere in the cluster itself.

Link to comment
Share on other sites

I think what people have been telling you is that your dash cluster doesn't have a thing to do with how your car is running.

 

If I skimmed the thread as well as I thought.

Link to comment
Share on other sites

that is correct. from what i gather there is no way that the digital cluster could cause these problems because the cluster does not control anything, it just reads the outputs

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...