Pliant

]Ok since we are here and on this topic.....question if i may..ok GM tbi injectors dont do well over 20lbs of pressure yet mefi calls for 30...is this corrected by the on board or inboard tbi pressuer regulator????aka the spring in the diaphram????

nunnink23

SB, good call on the t-stat ground. I checked it, perfect cotinuity.

I will try the timing light approach, but let there be no mistake, this is a rich condition. I pulled the plugs out, and they are black as night. It's not burning oil either.

Yes I am running water through it now. I even tried taking the water circulation out of the fuel cell, in case it was somehow mixing with fuel. Even after 15 mins with no water in the fuel cell no change.

Also ran another independent fuel tank today, with brand new fuel. I must have ran .25 gallons through it, no change.

IMO it's running ungodly rich, but I have no idea why. I will try one more time to make sure the TBI is sealed right, but if it was leaking why wouldn't it leak with the engine off, but pump on? I see your point about misalignment though. I did notice that the standard injectors don't stick as far down out of the injector pod.

Is it possible that the TJ11's are actually NOT the right ones? I hate to keep going back to these injectors, but after I find that IAT sensor, and replace it, I have nothing else to replace.

What diag tool should I buy?

nunnink23

Also, forgot to mention, yes my timing is now 8 BTC on the money. Doesn't jump around at all once in base timing mode. Last year it jumped around a ton, but my timing chain was stretched. I replaced that over the winter, and I'm. 99.99% sure it's not off a tooth. If it was I don't think it would run as smooth as it does. I had a friend who was a mechanic for 1 years check it before I bolted the timing cover back on.

Could a lack of back pressure from not being in the water cause SOME of this? Obviously not the cold start problem...

Sorry for so many posts.

BUP

I guess I can not get on the same page as you about what you are trying to accomplished - with that said here is what I am talking about as what I thought you were talking about . Please watch the vid, this is the best I can do to show you without writing a story book as I thought you were doing this exact test in the vid. Probably my fault because I am not following all the posts.

https://www.youtube.com/watch?v=SdlNwm8OHco

BUP

next - are you sure you are matching up all the correct sensors including the correct MAP sensor - A WRONG MAP sensor and or a bad MAP sensor will cause badly rich running condition.

Are you testing the MAP sensor ?

nunnink23

BUP, I was testing the same as that video. I can try the blip test tomorrow but it probably won't work because it won't respond to throttle input quickly.

I tried using the original MAP sensor, and the new one, and both caused the same condition. I've actually swapped all the new and old sensors. None changed a thing.

So if my vaccum increases with rpm's I have a problem? If so, I have a major problem. I didn't go above 2000 rpms, but it certainly increased with engine RPM.

SB - where did you find the SU107 part number? I went to 4 parts stores today and nobody was able to help me. Napa got the closest but no luck. I even had the sensor, plus the walker products part number from Rock Auto with me. I will see if I can find one of those part numbers locally tomorrow.

BUP

Sorry on my part - Vac testing like in the vid is really what I am referring to - when I said that's not how it works meaning you are trying to increase rpms and leave it there at the higher rpms as we both know your engine is running poorly even while increasing rpms and that's not how you vacuum test. Many of the vac tests are at idle, I was referring to. I should have used the word blip the throttle instead of advancing my bad. I'm glad I found the vid for whomever to show what kind of problems can be found with the vac gauge.

nunnink23

I am glad you posted it too. I spent the last hour reading about vaccum testing. I found it really interesting how much you can learn with a vaccum test.

I just don't know where to turn next, outside of the IAT sensor.

BUP

Volvo part number for the injectors per your app are 3857398 and yes it is an OMC & Volvo part number as well. They are NLA but if you can cross reference this number to an aftermarket. I believe I can still get the injectors for this. Volvo listed there TBI injectors by a color code as well. Volvo listed your injector color code as Black / yellow. - FWIW

Also the MAP Sensor for your app thru Volvo lists out of stock for a long while , So where did you buy a new MAP ? that part # is 3850396 and is both a Volvo and a OMC part number so maybe you can cross this to yours or whomever makes this cross. Just saying. You can Ohm test your coolant temp sensor l to make sure it is within spec. .

SB

Schweet. In my notes about the black/yellows:
=================================
25170301
61 pph @ 13 psi
NOTE: used on some marine engines at 26-32psi
100 pph @ 30 psi
=================================

Now, the common 5.7 truck/car injectors are the 5235206's (orange/black) whuch typically flow near/at the 61pph at 13psi too.

More tomorrow. I just came in, saw the email with response by BUP, and my mind got triggerred. It happens, lol. Had to respond before I forgot.

Oh, BTW: #'s I have listed above ae what are stamped on top of tbi injectors