2000 5.7 GSi PEFS MAP sensor?

[alldodge]

I just looked at their website and it mentioned opening up the TB. They may not have done that, just a question.

From the site I'm not seeing much which tells me most of their work is with autos. Noticed they pay more for a core with the marine injectors, which would agree because you cannot get them anymore. It doesn't mention how their tested. The 3 week wait also has me thinking its a small shop and unsure just what kind of expertise they have

 

[ChrisCraftFan]

I saw other forums that highly recommend him as knowing TBI's well. He helped me try to diagnose and he seemed that he knew what he was talking about on the difference between Marine and Auto. Understanding the injectors are different and keeping OEM injectors is important if you can. Had mine done in 2 days. There really isn't much inside these things as far as I know. He kept the regulator spring and replaced diaphragm. other than that its injectors that got cleaned and tps and iac. Unfortunately it made no difference at all same symptoms.

 

[ripjmk]

Your probably right with regard to the knock sensor but just to be clear the first action it does is to increase fuel. The attached is probably too small to read but it is page 29 of the VP EFI Diagnostic Manual which describes the operation of this system.

 

[ChrisCraftFan]

That is an interesting piece of information. what is the document you are using I may want to get one of those. I think i need to watch my scan carefully. Maybe knock sensor shows up momentarily when i mash the gas??? I didn't see it but I will look closer next time. I can record the scan and watch it back in slow motion.

 

[ripjmk]

VPA 7742218 03-2003
I can't remember where I got it from, there are sites on the web you can download it from, but I can't vouch for any of them, could be risky!

 

[alldodge]

That is an interesting piece of information. what is the document you are using I may want to get one of those. I think i need to watch my scan carefully. Maybe knock sensor shows up momentarily when i mash the gas??? I didn't see it but I will look closer next time. I can record the scan and watch it back in slow motion.

Even if the knock was only for a split second and then went away a code would be recorded. Your scanner would then show if it was active or not

 

[ChrisCraftFan]

oh crud bucket! I know there is not a code darn! I am looking for anything that will give me some light in the tunnel. LOL

 

[ripjmk]

I'm not aware of a" knock detected code" only a KS inactive (faulty sensor) DTC44. The KS circuit works all the time as a normal operating parameter.

 

[Tail_Gunner]

oh crud bucket! I know there is not a code darn! I am looking for anything that will give me some light in the tunnel. LOL

It is quite apparent you have a fuel problem, with that being said you also had this tbi modded by a professional enthusiast?
The fuel pressure spring in a marine tbi is 18psi...auto is 13psi. I would give this guy a call and confirm what he has put in your unit.

As to injectors the 17's I posted work well with mefi3, with that being said here is another old part no. i have. The below are remans, Napa is good to work with

TBI - GM, 7.4L, 5.0L, 5.7L - Volvo 5.7L Marine, Reman/Refurbished

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www.fiveomotorsport.com

https://www.napaonline.com/en/p/CRB217058A

A note here GM throttle body early nickname was Slobber Body, That is not being sarcastic nor demeaning....there was a reason for that. It runs much in the same vein a Quadra-Junk...not everyone could work on them...and that was 30 yrs ago..

GM TBI SPRINGS https://www.google.com/search?q=18+...KHcggCDoQ_AUItAIoAA&biw=1094&bih=474&dpr=1.25

 

[alldodge]

I'm not aware of a" knock detected code" only a KS inactive (faulty sensor) DTC44. The KS circuit works all the time as a normal operating parameter.

I have the same manual and it does not list the GSi, but is for TBI

Lets try this, you say its being done by the knock sensor but have not provided anyway to determine that is what is happening. How does the OP determine this is what is happening?

Maybe: Disconnect the KS and if its the KS causing the over fueling at idle? Should see a code 44 upon throttle up but maybe not the over fuel, tell us whats going to happen?

 

[ChrisCraftFan]

Well he didn't "mod" the TBI just replaced gaskets, cleaned injectors and replaced tps and iac. I worked on many Quadra jets in my day. I think I still have one in my garage off of an old mercruser?? No way this is as complicated as that. There are no settings to it at all that you worry about when replacing gaskets. I do LOVE the name Slobber body. (Laughed out loud at that) Did not replace the spring. I thought it was 30 psi?, could be wrong but, it was not replaced. He was very aware of the difference and that replacements are near impossible to get.

I found the EFI manual for the 5.7gsi but only in hard copy and will take two weeks to get here. not sure if i pull the trigger on that or not. ($25)

I will be checking the knock sensor carefully but skeptical. You just never know. could be something that compounds the issue. I like the idea of unplugging it. I can also record the scan and watch in slow mow.

I truly appreciate all the input folks, keep the ideas coming, we can do this!

 

[ripjmk]

I'm not sure disconnecting the KS is a good idea, I'd make sure all the other diagnostic guide items have been checked first. Maybe the attached checks (many of which have been covered) would be appropriate.

 

[Tail_Gunner]

Well he didn't "mod" the TBI just replaced gaskets, cleaned injectors and replaced tps and iac. I worked on many Quadra jets in my day. I think I still have one in my garage off of an old mercruser?? No way this is as complicated as that. There are no settings to it at all that you worry about when replacing gaskets. I do LOVE the name Slobber body. (Laughed out loud at that) Did not replace the spring. I thought it was 30 psi?, could be wrong but, it was not replaced. He was very aware of the difference and that replacements are near impossible to get.

I found the EFI manual for the 5.7gsi but only in hard copy and will take two weeks to get here. not sure if i pull the trigger on that or not. ($25)

I will be checking the knock sensor carefully but skeptical. You just never know. could be something that compounds the issue. I like the idea of unplugging it. I can also record the scan and watch in slow mow.

I truly appreciate all the input folks, keep the ideas coming, we can do this!

It would be quite wise to obtain the Volvo manual, there are a lot of commonalities in marine injection and a lot of small variations. It is not one size fits all, A bit lit like marine blocks are different from auto blocks....when in fact it was all due to what was on the shelf at the time...no more no less...But that Is another story.

30 psi on the fuel rail, 14/18 lb springs on the regulators... To the Rochester, i am currently refreshing a 83 454 smog motor..HEI/Rochester stuff. What an absolute pleasure, it is such a simple system and with instant results, don't like one timing curse just a spring away or a simple nudge or a quick vacum adjustment it is very liberating.

It is good to know you worked on carbs, at some point those injectors dumping at low loads will bring you to a conclusion...Carbs are so simple.

 

[alldodge]

I'm not sure disconnecting the KS is a good idea, I'd make sure all the other diagnostic guide items have been checked first. Maybe the attached checks (many of which have been covered) would be appropriate.

So you got nothing to add but post another page from the manual

 

[alldodge]

CCF
Nothing would happen that could not be cleared by the scanner of the KS was disconnected. If a code 44 showed up it can be cleared.

Start up let idle and then disconnect and have the vacuum gauge connected. If no code is thrown then the ECM is not increasing fuel. Throttle up and see what if anything changes

 

[Tail_Gunner]

Your probably right with regard to the knock sensor but just to be clear the first action it does is to increase fuel. The attached is probably too small to read but it is page 29 of the VP EFI Diagnostic Manual which describes the operation of this system.
View attachment 333020

Is this manual a mefi 1/3 or 4 and or above, I have never seen a burst of enrichment in mefi 3. Aside from the cold enrichment circuit

 

[ChrisCraftFan]

i guess I should get the GSI manual. Probably not the last time I will be searching for answers. LOL. With a name like slobber body this may be more like a lifestyle. Thanks to everyone I have a few things to check. I might not get to it until Saturday. Just too much going on. Sunday is all about football party! Go bucs! And please keep the ideas coming. Very much appreciated. I need to get back on the water. It’s my favorite place to be

 

[ChrisCraftFan]

Mefi 3 Got a spare?..

sorry you are asking about the manual. My bad

 

[ripjmk]

The EFI diagnostic manual TBI section is for MEFI 3, the PFI section is for MEFI 4.

 

[Tail_Gunner]

i guess I should get the GSI manual. Probably not the last time I will be searching for answers. LOL. With a name like slobber body this may be more like a lifestyle. Thanks to everyone I have a few things to check. I might not get to it until Saturday. Just too much going on. Sunday is all about football party! Go bucs! And please keep the ideas coming. Very much appreciated. I need to get back on the water. It’s my favorite place to be

Take a neon light as stated and have a gander down body when she's running. Notice the injectors slobbering all over the butterfly, perhaps watching the injector spray pattern during this off idle stutter/bogging might be eye opening. Spindles in the injectors can last for only so long before they lose there ability to meter fuel..Im pretty sure those cheap led lights will strobe the injector spray pattern.