2000 5.7 GSi PEFS MAP sensor?

[ChrisCraftFan]

Led lights or neon light? I have led flash lights but not neon. Maybe I can somehow justify a neon bar sign stating that ” I need it”.

 

[Tail_Gunner]

Led lights or neon light? I have led flash lights but not neon. Maybe I can somehow justify a neon bar sign stating that ” I need it”.

It has been years since I've played with TBI, in 07 I used a shop handheld light, very bright white I assumed it was neon I will now amend that to florescent...Age makes the mind wander...

https://www.grainger.com/product/39AM82?gclid=CjwKCAiAjeSABhAPEiwAqfxURb8IkyItTHTnlaf1OPOEM1TJjZhHXvYp6tT8rAMDK6p2k-tvZg643BoC0j0QAvD_BwE&cm_mmc=PPC:+Google+PLA&ef_id=CjwKCAiAjeSABhAPEiwAqfxURb8IkyItTHTnlaf1OPOEM1TJjZhHXvYp6tT8rAMDK6p2k-tvZg643BoC0j0QAvD_BwE:G:s&s_kwcid=AL!2966!3!281698275492!!!g!471548658361!&gucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231

 

[ChrisCraftFan]

Just ordered the 57Gsi efi diagnostic manual. I should have it in a week I think. Meanwhile I will try an LED spotlight I have. Not 100% sure what I am looking for with the light though?

 

[Tail_Gunner]

Fir

Just ordered the 57Gsi efi diagnostic manual. I should have it in a week I think. Meanwhile I will try an LED spotlight I have. Not 100% sure what I am looking for with the light though?

Just a opinion: You have a combustion problem, in your initial post you stated high map voltage at idle with low vacuum

Finding vacuum leaks

www.crankshaftcoalition.com

There are several methods for locating vacuum leaks. If you suspect a vacuum leak on a carbureted or TBI engine, you may be able to verify your suspicion by performing a simple check. With the air cleaner removed and the engine at idle speed, use the choke blade to partially block the airflow into the engine. Or you can place a wadded-up rag lightly over the throttle body throat to partially choke off the air supply. If this artificial richening of the air/fuel mixture causes the engine rpm to increase, you may well have a vacuum leak.

Often a vacuum leak will cause a whistling or hissing noise. Use an automotive stethoscope or even a length of vacuum or fuel hose to listen for the vacuum leak with the engine idling.

A stethoscope is self-explanatory. To use a piece of hose, put one end of the hose by your ear and use the other end to probe around for the leak.

Warning Warning: Stay away from any moving parts like the belts and fan blade. the fan or fan belts.

Warning Warning: NEVER use a long screwdriver or other stiff object to locate engine sounds! This type of thing could kill a person if it was jammed into the head.

Enough of that.

Using a florescent light at this point only takes a second, one can see if the injectors are acting correctly. They are 25 plus yrs old, that merits a quick look see.

The above two approaches only take 15 minutes, if you don't find any issues move on to different systems in the fuel delivery process.

It would seem apparent the Mefi is not throwing codes to rely on. Checking the individual systems can be quick and illuminating.

Alldodge has taken you thru the systems you are overlooking something small, and that is easy to do. Don't rely on the Mefi to guide you.

Lighting up the injectors, at low rpm the spray/ shower is low, it turns into a heavy shower as the rpm increases. Is that process linear. It takes only a few minutes.

 

[ChrisCraftFan]

I will plan to do all that testing. I am, however, pretty sure I have a vacuum issue. its at 16. Tracking down why has been my absolute nightmare. Also pretty sure the injectors are dumping too much fuel. (Black smoke) So probably slobbering when I hit it with the light. One one the reasons I am pretty sure that needs to be fixed is the vacuum talking to the MAP and MAP telling ECM more fuel based on voltage too high.
Great ideas for testing! I even have an automotive stethoscope buried someplace in my toolbox. LOL
I wonder if that would hear the leak if on the underside of the intake? surely worth a shot!

 

[Tail_Gunner]

I will plan to do all that testing. I am, however, pretty sure I have a vacuum issue. its at 16. Tracking down why has been my absolute nightmare. Also pretty sure the injectors are dumping too much fuel. (Black smoke) So probably slobbering when I hit it with the light. One one the reasons I am pretty sure that needs to be fixed is the vacuum talking to the MAP and MAP telling ECM more fuel based on voltage too high.
Great ideas for testing! I even have an automotive stethoscope buried someplace in my toolbox. LOL
I wonder if that would hear the leak if on the underside of the intake? surely worth a shot!

Yes using hearing a leak in the valley is a reach, yet that article does touch base on such a occurrence...

"Untraceable" vacuum leak​

Occasionally on engines that use the intake manifold to seal the lifter valley, you may experience a vacuum leak from the lifter valley area into the intake ports. This may be due to a bad gasket seal or because the intake manifold-to-cylinder head interface was not machined parallel (usually done to correct for milling cylinder heads and/or block).

No amount of propane or carburetor cleaner will find such leaks. The best way to ensure there's no such problem is to use quality intake gaskets installed correctly and to double-check any machining before the final assembly of the engine.

These can be found by removing PCV and plugging PCV hole and attaching vac gauge to PCV inlet, then seeing if crankcase develops vacuum! GM 3.1, 3.4, and 3,8 engines have these problems often.

​

 

[ChrisCraftFan]

I have not had time to work on the boat. I am thinking about replacing intake gasket this weekend. Watched a lot of video on vortec gaskets. Apparently the plastic ones are junk. Looking at the fel-pro problem solver gaskets. They have an aluminized steel carrier. everyone is raving about them. Looks like water jackets are very well covered in their special rubber. Anyone use these. Concerned about salt water bu t they look well sealed to protect them.

 

[ChrisCraftFan]

Update - removed intake this weekend. When I cleaned the gaskets all off and placed the intake on with no gaskets at all I could get it to rock a little bit across corners. (Diagonally) decided to take to machine shop to make sure it is flat and not warped/twisted. I did have to remove valve covers and risers to make the removal and install go much easier. Now I am debating myself again on the riser gaskets. I got the ones from Barr when I bought the exhaust system but opted to order the VP metal gaskets. Now I am wondering it it is worth it for the metal gasket again. they are probably 3 times the cost! I overthink everything LOL

 

[ChrisCraftFan]

So here is a picture of my intake half way thru the resurfacing. I may have found my vacuum leak! I hope to get it back on this weekend, if I can get some time. Hopefully up and running again!! I again want to thank everyone for input. Its been of great value to me!!