OK, It does not appear to be mechanical, whew.

I do not see any exhaust leaks, however, I will double check. I will tighten down the header bolts if need be. There is no EGR and it's blocked off on the intake.

Thanks guys. Anything else I should be looking at?

 

Hey Buddy,
You find anything else to report?Just very curious and hope its all going well for ya!
A TTT for ya too!

 

Sure you have the chip inserted correctly? Is the chip programmed for larger injectors and is it a good tune? The chip plugs into a memcal then into the ECM. I forgot to plug Alvins chip in without the memcal and ended up fouling out my new plugs.

 

Yep, checked that.

 

65Z01 stopped by and we tested the injectors, taking one out at a time.

We pulled the fuses for the injectors, hooked up my 200amp battery charger and turned it over and over. No noise, nothing. So I don't believe it's mechanical.

I went over the wiring and the firing order is correct, and in the right spot. I went around and pushed in all the spark plug wire connections. One was not clipped in all the way into the cap. I have had that problem before, however, it never resulted in this gunfire type sound, usually it's just a miss.

I couldn't start the car as my garage is directly under my 8 year old's room. I have to try it again in the morning.

 

Thats great 65Z01 came to assist! Good Luck and keep us posted what you find!

 

Started it this morning, no change....

 

as the injectors were just replaced. One injector is very noisy! It will make a hellava racket

I had the same problem with my son's A4 Audi when we changed out the timing belt. The noise went away as the engine warmed up.

 

if its not knocking when turned over then its got to be worth taking it for a gentle drive surely? See what its like under light load etc it might give you a few more clues of where to look?

 

I'm afraid. I have a couple people I want to look at this with me before I try that. I thought about it. But I'd like a second, thrid, and fourth opinion....I'm not the gamblin' type.

 

One of the tests I did was to unplug the injectors one at a time, then start it. Did this for every injector, same thing.

Perhaps it's more than one injector? Is that possible?

 

Is the rail forcing injectors down to tight? I had to shim my fuel rail with a few washers when I changed my intake. You can run a search about this, there should be my old thread or others from awhile back. If the injectors are forced down like that they will be very loud!

Edit, what your describing sounds to loud to be injectors. My next idea would be electrical snapping, that would be very loud and cause rough running. Wires OK?

 

I just changed my injectors. I have a Superam. One thing that I was really worried about was dropping a nut or bolt down the intake. I actually duct taped them shut while I was working on it. I was also careful not to let anything drop down the hole for the injectors. I think something may have dopped down an injector hole. I think you could have something sitting on top of your cylinder in the combustion chamber. I hope I'm wrong and it's something easy to fix. What injector did you use?

 

Here' what I'm thinking after making calls and gathering information.

I believe the tune may be out.....or the injectors too big..STFU....

What may be happening is the injectors are feeding too much gas in open loop and washing the oil off the cyl walls and I'm getting noise from the pistons as a result. That would explain it....seems most reasonable.

I am getting a set of injectors to try. I have a call into PCM For less to discuss the Tune. What a PIA...

 

Sorry. That is NOT most reasonable. No way!

RACE ON!!!

 

OK, I respect your opinion so I will lay out the facts as I see them and please tell me where I'm wrong.

1. THe car ran fine
2. I replaced the injectors only
3. The car makes this wrapping noise. Only ran it in 5 second spurts.
4. The timing was 6* dead on before the switch, and I did not move the dist
5. Double, triple, quadruple checked the sparkplug wires in both position on the cap and firing order
6. New chip programming
7. Spoke to engine builder. In the old days when they used to build engines and let them sit a week or so before starting them, they would clatter like all hell, this was a result of the oil running off the cyl walls.
8. It is possible that the tuning on the chip was not altered in closed loop for the larger injectors spilling all kinds of liquid gas into the cyl that could not atomize becuase lack of engine heat. It's a theory.
9. With the condition given in 8, the gas would not burn and likely to clean the oil off the walls of the cyl wall.

I just have not heard any other feasible, credible opinion put forward. I am going to swap to smaller injectors, hopefully this weekend. It's an easy, inexpensive way to see if this theory holds up. If the noise goes away with the new injectors, then I know where the problem is. IF it doesn't, then I have to dig into the motor.

Yes, at some point this is trouble guessing. I took on this project as an educational experience, and it has been just that, to a fault. So I'll know more about this by the end of the weekend, maybe early next week.

 

If the injectors were dumping that much fuel, you'd have gas in the oil. It would be very runny and smell like gas. How big a jump in injector size did you go?


Good luck, Paul

 

22 to 36, however the new injectors are marked 40. Racetronix says that they are marked 40, however flow 37 as per their website. However, their flow is done with Heptane, I don't run Heptane in my car, I run GAS. So in email exchanges with Racetronix, since there's no phone number, we determined the real flow is 38.25. for the life of me why can't these manufacturers post GAS flow numbers and end the dam confusion!!!!!

Based on all empirical evidence, I can have the new injectors in, in about 1.5 hours and give that a shot. I am "borrowing" a set of 24 lbs just to try and see if the noise goes away. Cost me nothing to try.

I started out with 22lbs which were a bit small for the motor as the car was running lean.

As to gas in the oil, the car never ran that long. I will check it. I thought about that, we'll see.

If anyone has any suggestions on a troubleshooting procedure that at this time does NOT require tearing the engine down, I'll be glad to listen.

 

I couldn't even feel the injectors click while the noise was comming; with my stock '88 injectors I can both hear their click and feel it with a finger on the wiring harness.

 

Based on what you heard, does the explanation seem realistic?