HELP

[mystang]

Need help with diagnosis.

Little back story, I have replaced every single gasket or seal on this engine except the head gaskets. I have had everything apart and have put it back together. Good news is the engine dosent leak anymore, bad news is when I try to time the engine. with ETC disconnected at 6 degrees BTC, the car idles up to aroud 1200 to 1500 rpm. If I advance to ATC it will idle down, but I am not able to see the timing mark? ;help Also after a few minutes the headers start to glow cherry red no matter how i set the timing.

Secondly, it smells a bit rich and check engine light is on. after pulling the codes i have the normal #12, then #14 (Engine coolant Temp (ECT) sensor- Circuit low or open circuit. #33 (Map sensor signal voltage ouf of range, high) I believe that the headers are glowing because of alot of fuel in the exhaust, and the map sensor "issue" could be part of it? Also #42 (Electronic spark timing (EST) Circuit grounded or ignitinon control (IC) circuit grounded or faulty bypass line. (Is #42 not expected when you have to pull the bypass line loose to do the timing?)



I have not had a chance to check map sensor or incoming voltages. The coolant sensor could be messed up when I was cleaning the lower intake manifold . but the map that one has me thrown for a loop as i have the vaccum line plugged into the manifold and I even replaced the vac line, but changed it back to the old one after the codes?

Is there a fuse for this item or items.

 

[mystang]

Okay lets back up again. I replaced rear main and oil pan, car ran fine after, then replaced valve cover gaskets, car ran fine. still noticed the car leaking so after much search discovered i may want to take a look at intake manifold and oil pressure sending unit. Took out distributor and pulled manifold. Resealed manifold, but I took the TBI off of the manifold which I now understand was a big NO NO. Instead of putting it back together i went in for the timing chain cover as it was also leaking, after putting it all back together tried to crank. It would crank, but no dice would not start. So started messing with clocking of the distributor and still no go. Let it sit for a few minutes thinking maybe flodded.

I then go to crank it and it starts but stumbles for about 10 seconds. Did this three times. Finally was quick enough to get the timing light on it and when I would put it at 6 Deg. Before TDC it would just make a ppsh sound and Die. So tried this a couple more times then it cranked and ran "fine". Except it idled High at 6 Deg. BTC and the headers would start to glow red after a few minutes throwing the codes listed above. I checked the Map sensor ground and voltage as well as output voltage. All check out to be good.


Then about a week later I took another stab at it and now it would even start on its own, but it will crank until the battery dies. So thinking that I may have messed up on the timing chain went back in and took a look and re verified that I have dot to dot aligment with both sprockets. Also made sure that I was not 180 Deg. out with the distributor. As in when dot to dot it was pointed at #6 on the cap. So any ideas hnoes?

 

[topless82vette]

are both injectors spraying and does it have good fuel pressure? replace ECT sensor with newer style one, all that fuel could have plugged the cat. bang on cat see if it sounds hollow or pull it and look into it. to much fuel in a cat = instant death.

 

[nelson84]

What is a ECT?

Please type all the words? Do you mean the collant temp sensor?

 

[mystang]

are both injectors spraying and does it have good fuel pressure? replace ECT sensor with newer style one, all that fuel could have plugged the cat. bang on cat see if it sounds hollow or pull it and look into it. to much fuel in a cat = instant death.

Yes I have fuel and spark everytime.

 

[mystang]

Also which sensor is the coolant temp sensor, The one on the passenger side I believe is the radiator fan switch, there is one on the front of the intake manifold below the smog pump and then one towards the front of the driver side, I believe it is also in the head.

 

[killain]

If I read your posts right, you have the timing advanced too much. If you have the timing advanced too much you increase the heat in the cylinders and the exhaust is going to run hot as well. If it were me, I'd go back and reset the timing with #1 piston on TDC. 2. I'd clean the timing marks and use a white piece of crayon. It's not going to run right till you get the engine timed right. The engine temp sensor is on the drivers side head just forward of the manifold. And before you attempt anything else, Go get a Haynes Chevy Corvette 1984 thru 96. It has excellant details as to how to time the engine and it only cost about $15.00. Without this everyone here is guessing as to what is your problem.

 

[mystang]

If I read your posts right, you have the timing advanced too much. If you have the timing advanced too much you increase the heat in the cylinders and the exhaust is going to run hot as well. If it were me, I'd go back and reset the timing with #1 piston on TDC. 2. I'd clean the timing marks and use a white piece of crayon. It's not going to run right till you get the engine timed right. The engine temp sensor is on the drivers side head just forward of the manifold. And before you attempt anything else, Go get a Haynes Chevy Corvette 1984 thru 96. It has excellant details as to how to time the engine and it only cost about $15.00. Without this everyone here is guessing as to what is your problem.

I believe I set the #1 cylinder at TDC and I colored the "notch" on the harmonic balancer with some white model paint, so I can see it. I checked to make sure that the harmonic balancer had not spun or slipped. Looking at the Haynes chevy corvette manual 1984-96 it states that when the timing chain gears (crank and cam) are dot to dot that is #6 at TDC, so I pulled the cap on the distibutor and it was pointed at #6.


Also when the car was running it the headers would glow if it was very retarted timing "after on the timing cover" as well as 6 Degrees BTDC. So to me it seems like a fuel issue, but then why would it not even start now is what I dont understand, because I have fuel and spark. and pretty close to the correct timing?

 

[mystang]

I have been looking around, does anybody have a picture of this black rubber "manifold" that is bolted down on the passenger side of upper intake manifold "plate". It has a few vaccum lines (hard plastic) coming to it. I believe one connects to the egr valve, one that goes to the bottom of the passenger side TBI and there is one that has a metal clip on it facing the front of the engine, but I have no vaccum tube to go to it, Anybody know where this should go?

 

[mystang]

SOLUTION

Okay after rechecking everything mechanical for about the fourth time, I finally said screw it and got the car towed. I must say this is a first time for me not being able to figure out something, but I knew how it was reacting that mechanically it was perfect. I knew it had to be a sensor, and not having the correct tools to diagnose I had to send it to a shop. Well it turns out that the MAP sensor was the issue, now the chilton manual states that at a certain vaccum it should read 2 volts, well I had a hand vac pump and it read about 2.3 to 2.4 Volts. Most of the time they give you a range of voltage, so I figured it was good as it responded smoothly and quickly with change of vaccum. This was about four weeks ago, I even had a new one in my hand not but three feet from the car and returned it thinking it was not the issue :bash. So at this point the map sensor being the issue was last thing on my mind. I was more pissed at my self then anything, so I hope this helps somebody out with a similar issue.