Intermittent SES Light

[c4zr1]

Well I thought I had my problem solved, but need some help. I did the AB pin jumper and getting codes 34, 44, and 54. I can drive the car about 5 miles and the SES light will go off and the secondaries start working. By the time I get back home after 10 or 15 miles the SES light comes back on.
I have checked and the vacuum pump and lines holds pressure, I changed the MAP sensor out. By the way I sent my ECM off to Tom Henry Chev. and had it rebuilt as well.
I wish I had a Mark or Cory close by, but I am way up in the Texas Panhandle and there does not appear to be anyone that knows anything about ZR-1's close by. If I have to I will load it up and take it to Mark or Cory, but I thought I would try solving the problem myself if I can.
Do I nned to invest in a Tech 1?
Any help will be appreciated.

Thanks!
Don

[Kevin]

well i wouldn't have sent anything to tom henry chevy. he doesn't really care about zr-1 owners. perhaps you have an o2 sensor going bad

[John Boothby]

Amarillo? I had to join the club and pay a buck to get a beer there with my meal! Not used to dry counties.

I am assuming you have a FSM? You have 3 different issues. 34=MAP sensor; 44 =O2 sensor and 54=Fuel pump. Were all your codes cleared when you installed the rebuilt ECM?

Sometimes the MAP sensor vac line can come loose. I tie-wrapped mine. Make sure your elec connections are tight. Or it could be a bad sensor. Wouldn't be the first time a defective part came off the shelf. Also, check all your pcv lines and connections.

A Tech-1A would help with the O2 and fuel pump volts. I have not had any problems with mine, so I have no experience with those.

Tech -1A's can be had for around $150-300 on fleabay from time to time. Be sure you get the correct modules. I havn't checked lately.

[c4zr1]

I do have the FSM's I will try and replace the 02's. Should I go with Delco or can AutoZone fix me up?
Thanks for the help John!

Kevin,
Tom Henry Chev treated me very well so I cannot say they did not take care of me for my ZR-1 needs.

[John Boothby]

Just follow the diagnosic charts in the FSM. I have used them before I broke down and bought the Tech-1A, and it worked pretty well. Just easier with the scanner.

I don't know about the 02's, someone else will have to advise you on that. I don't see why Autozone shouldn't be able to fix you up though.

Tom Henry Chev has always done right by me.

[tomtom72]

fwiw on the O2 sensors.....our OE ones are Bosch and autozone sells Bosch. the Bosch are a lot more money than the house brand. I bought the Bosch when I changed both of mine as I felt it might be a smarter choice?

My take on the codes: fwiw

34 = low signal voltage, high vacuum. possible oil clogging the MAP hose or the MAP hose is collapsing under high vacuum conditions. Or the MAP could be giving up.

44 = left O2 says that bank is lean. bad sensor or fuel filter clogged a bit or pumps are getting tired. This could tie into the DTC34.

54 = low voltage fuel pump. This code is used to detect a faulty fuel pump relay. Also the connection at the ECM could be faulty.


Tom

[Kevin]

i'm glad you guys had better luck with Tom then I did when they sprayed orange clean on my motor then washed it down...the parts guys have always been top notch though. body shop is great too

[scottfab]

Originally Posted by c4zr1

Well I thought I had my problem solved, but need some help. I did the AB pin jumper and getting codes 34, 44, and 54. I can drive the car about 5 miles and the SES light will go off and the secondaries start working. By the time I get back home after 10 or 15 miles the SES light comes back on.

Sure does sound exactly like what I saw when the secondary fuel pump stated failing intermittently. All was fine for the first few WOTs but just like when the vacuum pump works at 50% when an extended WOT happens the 42 gets set.
I eventually attached a pressure gauge and routed it up to the windshield so I could see it drop during the WOT. It dropped to 44 when the code set. A good secondary pump keeps it at 50 or so.
Good luck

[c4zr1]

I went to the local O'Reilleys and asked if they would put their scanner on my car.
Codes:
DTC-23 Manifold Air Temperature Sensor
DTC-35 Disconnected Manifold Pressure Hosw
DTC-46 Fuel Enabilar Failure
DTC-62 Oil Temperature High
I replaced the Manifold Air Temperature Sensor and the MAP Sensor
Took the car out for a spin. Still SES light. After about 5 miles the SES light went out I turned the Power Key on and the secondaries come alive for about a minute. The ses light come back on and stayed on all the way back home.
I rechecked the vacuum lines to the vacum pump and toward the plenum and it held vacuum ok.
Very Frustrated. I think it is time to take it to a shop.

[c4zr1]

Well I went back out to the garage and read through the Service Manual and found the section to read and clear the ccm and ecm codes. I went all through it. What was strange there were no codes in either that displayed.
I did discover a strange noise coming from under the plenum. It sounds like a ticking sound. Either a shorted spark plug wire sound or like a gasket blowby leak. I can hear it louder from the driver side top left side backend of the plenum. It does sound like it is under the plenum.
What do the experts think the sound is?
Thanks for your help!
Don