Howdy, i am fairly new to joining the thread. i have read it for a long time.. but any how i have a check engine light on in my 87 iroc with the 305 tpi. i pulled the codes and it has code 34 Low voltage (high vacuum) at mass air flow sensor (or MAP sensor), code 32 Fault in barometric pressure sensor circuit OR Fault in exhaust gas recirculation valve diagnostic switch OR Fault in electronic vacuum regulator valve and also in another post that i have in cooling already....just thought i should put this in so that you know all the symptoms not just a portion....also has cod 15 Low temperature indicated at engine coolant temp sensor. thx in advandce

 

bump

 

Well we can narrow a few of those code definitions...

Code 15 - poor electrical connection, open/short circuit on the coolant temperature sensor.

Code 32 - (TPI) EGR system fault, restricted vacuum hose to egr solenoid or valve, poor electrical connection open or short circuit, defective egr solenoid, defective egr valve.

Code 34 - MAF Sensor circuit condition, open or short circuit, defective MAF sensor.

Are there any other symptoms besides the SES light?

 

the only other sympton would be a bed heater core. The car has been sitting awhile and has a fan hooked up on a manuel switch

 

Make sure all your vacuum lines are in good shape for the EGR valve. Then run the car and manually open the EGR valve. This will tell you if the passage is clogged for code 32.

Code 34 - disconnect the MAF and see if the car runs better. If so, the MAF is bad. If not, you probably have a bad relay.

Replace the heater core and check to see if the coolant temp sensor is hooked up. It's the one in front of the intake next to the cold start switch. That might take care of code 15.

Good luck. Let us know what you find.

 

ok so i pulled off the maf and the engine dosent run any diffrent. so does this mean that the maf is bad? sorry for being such a newb

 

It is a good possibility that the maf is bad.

As for the temp sensor...
Is the fan on all the time or tied to kick on when the engine reaches operating temperature?

If it is on all the time and the gauge is working it could be triggered by the engine not being warm enough for closed loop.

I know this happens often on OBD II systems... But not sure if the OBD I is as sensetive to temperature.

 

the fan is on a manul switch. I plan to have it hooked to turn on on its own though

 

May resolve the problem. Or the temperature switch/sensor is why the fan didnt want to kick on to begin with. Either way once its wired back to normal that code should take care of itself.

 

I'm hoping so. I just bought the car and lets say that some people really did a number on some of the wiring.. Wish i knew who did it to tell you the truth. Just so i could ask them what the hell they were thinking lol.

 

I've come across some really bad jacked-up wire harnesses. If you have a diagram, and have the time to pull the harness out, you could check all the wires and make sure they are all in order and go where they need to.

 

Could be worse mine was so bad I had to basically put a hole in the firewall and start from scratch. New wires for all critical systems and diagnostic. Luckily the fuel gauge and speedo still worked (sorta).

LOL I found hidden behind the paneling where all the tail lights and fuel module wiring had been cut and respliced. Didnt find it until the tail lights quick working one day. Soldered it all back together and been working great ever since.

EDIT: oh oh and my favorite... to operate the cooling fan they ran a 12ga wire that was spliced into the harness at the fan itself and ran to a blade connector that was jammed into an open terminal in the fuse box. I could be b---- slapped for some of the ghetto things I have done to stay mobile when i was 'younger' but that just took the cake.

 

well on this one they ripped out one of those side dash pannels and just have the bare wires connected to a switch thingy for the fan. they had a oil pressure gauge(after market) and the light for it they ran a wire to the fuses.. not a big deal but the dummies put it on the fuel injector one so it was like off on off on....lol

 

Yikes.... sounds about right lol. I have an aftermarket oil gauge too mounted under the dash vents along with temp vacuum etc. But the original tach was replaced with an aftermarket in its place. Cutting through the plastic in the dash was no fun but it looks 1000x better than what it did. Oil pressure gauge loved to point straight up. And that wonderful tach claimed the engine was idling at 4700rpm and pegged off idle lmao.

The new gauge panel.



The voltmeter and fuel gauge I was able to get working again. Engine temp is still screwed up but I find head temp to be more reliable anyways. Can't see the wire bundle in this picture but its ziptied and awaiting some convaluted tubing come payday.

A testament to 'No matter how bad it is, it can always be saved.'