hey guys,
i need some help. my 94 Z is throwing an egr electrical fault code (27) and a code number 26. my car is bogging down at times.....e.g it won't go over 3000 rpms.
Any tips?
Thanks

 

26 Evaporative Emission (EVAP) canister purge solenoid valve circuit


27 Exhaust Gas Recirculation (EGR) vacuum control signal solenoid valve circuit


Sounds like an electrical problem. Check fuses first. QDM codes were for 93s only. One fuse powers both of the above and also the O2 sensors.

 

what fuses? i have checked the fusebox in the car and where the relays are. are there more?
my car is a 94 do you think i have a different pcm?

 

94 and 95 are virtually identical with regard to PCM and to fuses. The location of the "PCM BAT" fuse was moved in 95, but otherwise they are the same. Look in your Owner's Manual for the specific fuse assignments for your car. If you don't have a Manual, Shoebox has a link to online copies:

http://shbox.com/pdf/manuals.html

He also has an online code list that is specific to the LT1's. That would have given you the correct info, not confusing things with the QDM reference:

http://shbox.com/1/Dtcs.htm

Looking at my 94 Manual, fuse #6 in the under hood box supplies the fan relays, EVAP purge solenoid, EGR vacuum solenoid, low coolant relay and reverse lockout solenoid (M6 only). Same as 95.

Neither of those codes should cause the engine to bog down and not want to exceed 3,000rpm. But they may represent a problem with the O2 sensors, if its a fuse.

Describe the problem more fully. Apparently is will go over 3,000rpm under some conditions. Can you relate the problem to specific driving conditions - a rapid movement of the throttle, vs a slow movement of the throttle? What physically happens at 3,000rpm? Doe it feel like a series of misfires, stumbles, sudden loss of power, etc? How long has the problem existed? Did it develop suddenly or slowly over a period of time? Have you checked the spark plugs and wires? Coil? IC Module? How many miles on the engine? Has it been modified in any way? Did you make any changes just before the problem appeared?

Is your car an automatic or manual trans? Why not add a "signature" with basic info about your car - year, model, engine, trans and any major mods?

 

my car has a lt4 hotcam, the opti and plugs and plug wires are new. when i say it bogs down i mean that it overloads on gas and blows black smoke out the back while struggling to go over 3000 rpms. whether i am wot or just easing into it the problem persists. i have changed the ect sensor as well. im not sure of the mielage less than 100000 though. it will do it sporadically, but more so when i keep stopping somewhere then cutting the car back on ten fifteen minutes later etc. etc. and trying to go somewhere. its an automatic, too.
when it acts up it will be struggling for one minute all the way to 20 minutes. idk what to do about it. does that give you a little better insight??

 

Who tuned it for the LT4 HOT cam?

 

it didn't get a tune, but i bought it this way. and it was running fine when i bought it. but these are the codes that came off the modus scanner....
32- egr system problem
64-right O2 sensor too lean
27-egr electrical fault
26-quad driver module 1 fault
would my evap canister have anything to do with this? if it was bad or something?

 

Shoebox already told you that there is no "QDM" in a 94, and gave you the correct definition of DTC 26. He told you DTC 26 was for the EVAP canister purge solenoid. What part of this was not clear?

Scanners give you "generic" code descriptions. We gave you the link to Shoebox's SPECIFIC code list for the LT1. Do you not believe us?

You didn't list DTC 64 in your first post? Did you scan it again and find that added code? That could easilly explain your problem. You need to determine if you have a "false" lean code, or a real lean code. One way to check is to swap the O2 sensors from one side to the other. If the problem follows the O2 sensor (DTC 64 is replaced by DTC 44), you have a faulty O2 sensor. If the problem stays on Bank 2/right, its a wiring problem, or you have a problem with a vacuum leak, misfires on that bank, or exhaust leaks before the O2 sensor on that bank.

 

not tryin to **** in anyones wheeties here ,but i had the same problem when i did my cam swap same codes an all .brian herter of pcmforless sent me a tune over the e/mail and it wouldnt take so i sent him my ocm and i needed a new one .when ya have a quad driver fault it means the pcm is bad i guess

 

"What we have here is a failure to communicate."

Let's explain this for the 3rd time. Your 93 has a QDM. Yes, if it goes bad, the ECM ("ocm"???) may need to be replaced. The person who asked the question in the first place has a 94. The 94 PCM does NOT have a QDM.

 

mine is a 94 z ,i had a 93 also but that was sold .......i was referencing to my 94 when i replied

 

People aren't mind readers. That's why they created signatures.

 

Then why don't you put some useful info in your signature?

Still no QDM in the 94.

 

thanks for the help. it was my 02 sensors. just replaced them the other day and car is running good, but im still getting an egr electrical fault code. is that my solenoid?

 

The PCM looks at the voltage on the EGR vacuum solenoid circuit when the EGR solenoid is supposed to be on, and when its supposed to be off. If it doesn't see the voltage it expects, it sets the code. Could be an open or short in the solenoid. Could be an open or short in the wiring harness. I think the resistance across the solenoid coil is 15 ohms. Check it.