No check engine light is coming on at all.... The weird thing is that even if I unhook the battery to reset the PCM and hook it back up, right as it starts cranking to once it fires (right of the bat) is just starts dumping fuel in, as if it was suppose to dump that much fuel in. Its not like it runs a little bit and then progressively gets richer, but soon as it cranks it just starts dumping fuel in..

Its almost as if its not reading the piggyback at all, but it must be reading it properly cuz the PCM no throws on the check engine light and goes into fail safe mode (which is what was happening when the switching adapter was in it and not reading properly).. The one nice thing about it being set to run open loop should automatically mean that it is no longer making use of the O2s, and if there was one it would no longer be using the MAF, maybe the not using the ECT also, I am not to sure about that one... What sensors dictate A/F ratios in open loop mode? I have already changed the IAT which did nothing.. What about the MAP sensor? anything else that could do it? How much is a GM OBD I specific scantool for my car?

 

Open loop simply means that "learning" based on O2 sensor feedback is disabled. In a MAF car, the MAF is still used.... the PCM has to know how much air is flowing into the engine. Your speed-density system still calculates the mass air flow from the RPM, IAT, MAP and the lookup on the VE tables. The only real difference in open loop is "no learning". It is a popular misconception that in open loop the PCM disregards all the sensors..... its only the O2 sensors that it ignores.

The coolant temp sensor is used all the time. The ECM needs that reading to know if it has to RICHEN the A/F ratio for cold start - exactly the same function the "choke" has in a carb setup. If your coolant temp sensor is telling the ECM that the coolant temp is 20-degreesF below 0, the A/F ratio will be set ridiculously rich, because that's what it takes to start a car when the engine temp is 20-degF below 0. A faulty ECT sensor can easilly cause an engine to run excessively rich.

High MAP (= low vacuum) causes the ECM to assume the engine is under load, and it screws up the timing tables and the VE lookup, possibly causing it to run rich.

You need to get a data logger on there, and verify the operation of all the sensors.... simply checking them to assure yourself the data they are sending is rational. You can use my online scanner guide to evaluate the scan data:

http://members.aol.com/InjuneerZZ/ScanMast.htm

You can also verify the ECT sensor with an ohm meter. The table of sensor resistance vs. coolant temp is included in my reference document, and Shoebox has the test procedure on his website.

If you rule out sensor problems, then you are going to have to face up to it, and verify the timing chain and Opti drive shaft install accuracy.

Since the engine is running in open loop, the "BLM's" mean nothing.... they never change. Forget about them.

Have you ever done a code scan - no scanner required on your 93 because you can use the short the pins with a paper clip method.

 

I had the Coolant temp sensor plug break during a run at the track, and the video my friend showed me definitely shows the richness. Of course the Opti broke after that also, but when the sensor breaks it will make you run real rich.

 

I appreciate the help, that actually cleared up a quite a bit. I haven't read your website yet, but it seems pretty useful and I will do that.

How does this using short pins with a paper clip method to do a code scan work exactly???

 

I will just replace this when I get a chance on sunday now that I know that its acutally still being used, its only $20 and testing it on my car requires removing it and putting it in hot water to simulate conditions cuz there isn't enough access there to test with a voltameter (according to haynes), But if i'm taking it out, its not even worth my time to check it in boiling water, I mine as well just replace it.. Hopefully its that simple..

 

Injuneer, how does this paper clip and short pin method to do a code scan work? (even a website to veiw that explaines this would be quite useful, I noticed yours mainly covers only using a scanmaster..)

 

Shoebox has that covered too:

http://shbox.com/1/dlc2.jpg

My writeup was originally written to make up for the fact that the Scanmaster completely lacks any sort of serious operating instructions or guidelines on use. But the data presented, and the interpretation of the data is going to be valid no matter how you obtain the data.

 

If you have a scanner.... you can "in a rough way" figure out if there is a Temp sensor problem.

The IAT and the ECT will report similar values if the engine is left alone for a while for the temp to stabilize.


I figured out that the ECT and the IAT should report similar Temperatures after the car has been parked for several hours... because the temp has stabilized. So I put the scanner and just flip the ignition switch and compare readings... they wont be dead even but if they are close enough (within reason) then you can rest assured the sensors are OK.... You can also drive the car for a while til its hot... park.. let it sit in a non windy area for a while and then compare both readings.

If its windy dont bother... The IAT will report a diff temp than the ECT because its location will allow to adjust to ambient temp way quicker than the massive engine block will. I also have an idea.. drive the car... park... aim an Infrad Red temp meter right at the area where the ECT is at and compare with the reported temp from the sensor..... I know it wont be identical but it the readings are close then it should be ok.

Or the best Method. Buy a new one replace it and Mark it off your list of potential problems.

Marvin

 

I will just replace it.

 

Just to get this straight, with the paper clip test, the ECM will flash that DTC12 code and then if there is a trouble code present, The SES light will flash a certain number of times and the number of times it flashes is the trouble code?? And it will flash each trouble code 3 times, so there is just a pause inbetween each sequence of SES light flashes for the code it shoots out (cuz it flashes each code 3 times)? OR am I completely off about this..

 

The "code" will be flashed just like the "12" is flashed. If you had DTC 36, you would get 3 flashes, a short pause, 6 flashes (end of code), a long pause, repeat 3 flash - short pause - 6 flash (end of code), long pause, repeat 3 flash - short pause - 6 flash (end of code), long pause, then the next code repeated three times.

 

sorry, I'm not seeing how you would get DTC "32" out of "3 flashes, a short pause, 6 flashes (end of code), "

DTC "12" is "flash pause flash flash (end of code) long pause" (then repeats three times)

If the number of times if flashes before the "short pause" represents the first number of the code and the number of flashes after the "short pause" represent the second number in the code that would make sense for the "12" code, but for what you described (3 flashes, short pause, 6 flashes (end of code) wouldn't that be DTC "36"? I'm a little confused here.

 

Sorry.... see edit.... 3 flashes - short pause - 2 flashes.

 

Alright, now I am truely clueless on what the [ EDIT ] is wrong with my car. Today I replaced my ECT sensor and very closely inspected the mating connector which was definetly is very good shape, I triple checked the plug wires and they are all correct. I have already replaced my IAT. The EGR, carbon canister, and AIR were all removed and the codes should are deleted on this chip and also the O2s are disconnected and the ECM is set to open loop. Fuel pressure sits at 39 PSI, which is actually a tad low.. I wanted to test the MAP, but the multimeter I managed to get the broken multimeter from menards (I will test the volts tommorrow, but i'd put money on it being fine.) There also was never a SES light tiggered in the few minutes I ran the car. I also did a code scan and the only code flashed was "12" which just tells you that your in diagnostic test mode..

SO for the sensors that are hooked up that haven't been tested there would only be (besides MAP):
-The Throttle position sensor
- The Vehicle speed sensor
- Idle Air controller
- Knock retard is disabled

So none of those dictate A/F ratios so I already opted those out.

which neither of them dictate air/fuel

Also attepted to do a vaccuum test, this was pretty difficult being that it won't idle by itself (I have to keep giving it gas to keep the revs up, cuz once it drops below a 1000 RPM it just floods out and it very difficult, cuz the lightest tap on the gas pedal at a 1000 rpms shoots it up over 2,000 rpms), but I had my friend sit there with the vaccuum gauge and from what I gathered from him it seems to have really good vacuum, cuz it went up to 14 inches of vaccuum at one point, and it was ussually around 10-13 inches of vacuum (keep in mind the car was cold and also never actually at idle, I was hitting the opening the throttle constantly).... So I bet warmed up and idling by itself I bet it would be damn near 20 inches of vacuum, if it could get up to 14 inches blipping the throttle constantly, so that elminates the possibility of valves being incorrectly adjusted...

The one other thing that has been mentioned was incorrect distributor installation and bad cam/crank timing, but I truely don't believe that this is the cause of this, for a few reasons:
1. The car runs and drives with this timing (when plugs are clean), and seems to run fine (which if the timing was off, correct me if i'm wrong, but my guess would be that it would not run, or it would be backfiring horribly if it was slightly off.) besides the fact that its dumping a unbeleivable amount of fuel into the engine.
2. I did not do any of the work to the engine, it was done by 2 guys that work at dealerships, one is the top mechanic at a dealership and has done tons of engine rebuilds including his own car, his buddies truck (the other guy who worked on my car) and also they both had told me that they double check everything and that it was all perfect and that they beleive that its dumping in so much fuel cuz the for one the injectors were way too big (which they were) and the other was there was something wrong with the tuning (which at that time it was going into failsafe mode cuz I had bought a switching adapter from moates.net that must've been defective, cuz it was burned twice and it didn't work either time, but once i bought and put the normal adapter in it no longer went into safe mode, suggesting this one is actually reading.)

The only odd thing out of all this (I dont know, maybe my friend was just starting too see things cuz of the terrible amounts of unburned fuel fumes in the garage.) is that he did say that the vacuum went down really low (Around 6-8 inches) when the revs went down and that the vacuum actually went up (10-14 inches) when I gave it gas and rev'd the engine up, which contradicts the whole concept of engine vaccuum cuz its the absolute opposite of how it should be. So like I said, there were a lot of gas fumes in the air in that garage, but if anyone can make anything of that please let me know, otherwise i'm just gonna assume he was just messed up from the fumes.

Anyone got any ideas of what it could be, i'd like to say that it could be that its not reading the piggyback and chip aren't reading properly, cuz the car seems to run the same with the stock tuning as it does with this chip, but the ECM does not go into fail safe mode and trigger the SES light like it would if its not reading, so it doesn't make any sense what so ever. What else could it even be if its not my MAP sensor (which its prolly not)?? AND how is it not shooting out any kind of trouble codes even though its dumping fuel in like it is???

 

well, I went ahead and tested my MAP sensor with a multimeter, I tested the leads on the gray wire and it was at 5.10 volts, and then i tested the green wire and it was fine at the "on" position with the car not running and also with the car running... Also checked the oil dipstick and was just amazed, there is seriously a good 2 quarts of gasoline in the oil after only running the car a total of 2 minutes max, just to give you an idea of how rich this thing runs... is there anything else that could be causing this? What is it that causes these cars to run EXTREMELY rich with stock programming and a cam? Is there anyway too check to see if the piggyback adapter is reading properly??