Tps

[RUSSH]

Is it possible to have a bad TPS and not throw an SES light?

1995 Cutlass Ciera 3.1 auto

[BNaylor]

It is possible but uncommon for a bad TPS not to trigger a DTC code and SES/CEL light. You can check the reference voltage from the ECM module and then the output of the TPS as you vary the accelerator from closed to WOT.

What problem are you having? Is your Cutlass odb-i or odb-ii?

[RUSSH]

Originally Posted by bnaylor

It is possible but uncommon for a bad TPS not to trigger a DTC code and SES/CEL light. You can check the reference voltage from the ECM module and then the output of the TPS as you vary the accelerator from closed to WOT.

What problem are you having? Is your Cutlass odb-i or odb-ii?

How can you tell the difference between OBD-I and OBD-II? I've got the shop manual and read where you could check for codes possibly without a scanner, but stated some 94-95 models needed to be checked by a scanner.

It's been surging/fluctuating and dying when I press the gas to accelerate after it's at normal opertating temperature. It doesn't happen all the time, but happened this past Friday. Ultimately the car died. So I cranked it back up and sat for a couple of minutes, got back on the freeway and it did okay.

[BNaylor]

95 was a bad year because it was a transition year from odb-i to ii. There should be a data label located around the radiator area or support which may annotate what it has. Also, you can check to see if you have a 12 pin data link port. 12 pin is odb-i and odb-ii has a 16 pin, however, some odb-i models had the 16 pin port.

Here is a tech link which may help, especially if it is odb-i.

Click here

[RUSSH]

Originally Posted by bnaylor

95 was a bad year because it was a transition year from odb-i to ii. There should be a data label located around the radiator area or support which may annotate what it has. Also, you can check to see if you have a 12 pin data link port. 12 pin is odb-i and odb-ii has a 16 pin, however, some odb-i models had the 16 pin port.

Here is a tech link which may help, especially if it is odb-i.

Click here

If it is in fact the 12 pin, will I be able to get a trouble code even though the SES light is not on?

Do you have any ideas what the problem might be with the symptoms I've stated?

[RUSSH]

The car died on me again on the way home yesterday. I was even at cruising speed maybe 50 mph, not at WOT and it just died on me. I had to crank on it a couple of times and it finally started back up, but died again a couple more times before I finally made it home. Any ideas? I'd really like to get this resolved this weekend. I don't want to have to take it to someone.

[BNaylor]

Originally Posted by RUSSH

The car died on me again on the way home yesterday. I was even at cruising speed maybe 50 mph, not at WOT and it just died on me. I had to crank on it a couple of times and it finally started back up, but died again a couple more times before I finally made it home. Any ideas? I'd really like to get this resolved this weekend. I don't want to have to take it to someone.

Have you check for proper fuel pressure at the fuel injector rail and how old is the fuel filter?

Although you may not be getting any DTCs possibilities are the crank position sensor. There are two. A 24X and 3X. Also, a cam position sensor. Any one of these components could cause a stall out or hard starting.

It is either fuel or ignition related.

[RUSSH]

Originally Posted by bnaylor

Have you check for proper fuel pressure at the fuel injector rail and how old is the fuel filter?

Although you may not be getting any DTCs possibilities are the crank position sensor. There are two. A 24X and 3X. Also, a cam position sensor. Any one of these components could cause a stall out or hard starting.

It is either fuel or ignition related.

Well the car had about $1200 in parts put on about 3 months ago, including, fuel pump, fuel filter, fuel sensor, r&r injectors, replaced no.6 injector. Unless the car had some faulty parts put in, it leads me to believe it's going to be an electrical component. That's why I had my original question, because I figured something electrical would cause the SES light to come on. I'm gonna try and get some kind of code tonight by trying the trouble code check.


My next question is how do you decipher the codes. How does a SES light, pause, SES light, SES light= Code 12?

[richtazz]

A code 12 is "technically" no distributor/spark reference pulse. But since you're doing a key on/engine off test, that code should always come up first. Each code will flash 3 times, in numeric order. When it cycles back to 12, you're done retrieving codes. If a 12 is all you have, then there are no trouble codes stored. If you don't have a code list, post them here and we'll help you decipher them.

[BNaylor]

He's got all the possible DTCs Rich and how to decipher the SES/CEL light . See my post #4. His problem is not getting any SES/CEL light, therefore high probability of no diagnostic trouble codes.

http://www.troublecodes.net/GM/94-95_31M.shtml

[RUSSH]

Thanks a lot guys for your help. I will definitely post up the codes, if any, here when I get them. If I don't have any codes, then I wonder what the next step would be. Also after I start it...it does smell a little rich for a few seconds and then goes away. I forgot to mention that earlier.

[RUSSH]

Okay guys, here's the latest. I was gonna do the code test last night, but as stated in your link, some 94-95 models don't have terminal B. Well of course my car doesn't have terminal B. So I went to Pep Boys and asked him if they scanned it without a service engine light, would they find anything. He of course said no, but you can pay $84 for a full diagnosis and we'll tell you what's wrong. I told him what it was doing and he said it could be the Fuel Pressure Regulator. That sounds logical to me, but is there an easy way to test the pressure at the regulator?

[BNaylor]

It is possible but may be confirmed by checking fuel pressure at the fuel injector rail.

[RUSSH]

Okay last question. Can I check the fuel pressure without using a fuel pressure guage?

[BNaylor]

To test it effectively and see if it is in GM specs I doubt it. It is important to see the minimum pressure the fuel pump is putting out. There should be a Schrader valve on the rear fuel injector rail passenger side of engine where you can connect the gauge. They are not expensive. Around $25 at places like Autozone.


Checking fuel pressure GM 3100/3400