19# injectors not sealing causing vac leak/bad idle

[sienayr]

I have installed the Miller MAF, chip and 19lb injectors. Idle is terrible, so after testing MAF, TPS, O2 sensor, fuel pressure, new fuel filter, new spark plugs, I did another smoke test (had already smoke tested prior to beginning the job) and lo and behold smoke is pouring out of the injector area. I am pretty certain it's not the intake manifold as the amount of smoke is profuse and there were no leaks in that area a few days ago when I smoke tested.

I bought these (mainly because it came with six and not eight)
which are Bosch 0280150943 which seem to be the compatible ones people use:

https://www.ebay.com/itm/273938509436

specs:
https://www.injectorplanet.com/produ...sch-0280150943

Is it possible they came with a different size O ring that is not sealing, since it lists them for Chevy Buick Pontiac Olds 3.8L V6? Anyone experienced/heard of this issue before? Any guidance appreciated, thanks.

[superj]

yes, get a different o-ring set that's thicker

[sienayr]

After someone suggested that it might be the oil drain tube (which I was not familiar with, never pulled the intake on an m20) I was peering under the intake and it looks like it could be that, or even the intake itself after all.

So odd that such a large leak sprung so quickly. I changed the valve cover gasket, so I must have disturbed the intake or drain seal while the support bracket was off.

[superj]

it would be very hard to cause a leak at either of those without loosening the intake manifold nuts. just changing the valve cover will not cause those to leak.

i guess hook the smoke machine up again and look for exactly where the smoke is coming from.


when i upgraded my injectors t o ford v8 injectors, back in the day, i used an o-ring kit from the local hardware store. on the plumbing aisle is a section for changing stuff on your faucets and in that section is many different sized o-ring kits. i took the a stock o-ring and found the next size up and bought enough for my injectors. the inner diameter hole was a little larger but since the o-ring kind of stretches over the injector and than the other one stretches over the hat, it worked perfectly. those o-rings work fine even though they are not the same color or material as the ones on the car, but are a better material because times have evolved and newer materials are used on everything

[sienayr]

ok, so you have had an issue where the o rings were too small, causing vac leaks? I'll have to look again. It really seemed like the stream of smoke was originating from that drain tube area under the mani, or the runner right next to it. I did some cleaning when I had the fuel rail out, so I'm wondering if some crud might have ran down onto the old, assuming original, intake gasket and compromised it. Although I was being very careful as the spark plug holes were exposed.

[superj]

unless that oil drain tube was rusty and just happened to get a hole in it while you were working on stuff, maybe?

there is two large O-rings on the tube, top and bottom. but you can grab that tube and twist it in its spot and feel if those O-rings are good

[sienayr]

This has been a tricky one. The smoke helps a lot, but it can still be tough to determine where the leak is even with the smoke. I don't how people can find leaks with no smoke (I bought my 'machine' and a rubber cone on ebay for $85 total. It's a metal paint can with an element that heats up mineral oil, hook it up to a 12v battery and hook up air compressor to the 3 psi regulator on the can. Some of the best $85 I've ever spent. You could make one pretty easy with stuff from Home Depot.)

After observing the smoke more and considering superj's assertion that it would be hard to mess up the intake mani seal, I determined that it was neither the intake or drain tube. I removed the injector connectors, loosened the four fuel rail bolts, and with very gentle pressure using a pry bar pushing the injectors down I re-tightened the four fuel rail bolts. This fixed the smoke coming from that area; I think one or two of the injectors may have not been quite seated right. I also heard two of the clips click while I was pushing down, so they may not been seated quite right.

I still have smoke coming from the flange on the back of the intake mani where the fuel pressure reg vaccum hose plugs in, so I need to get a new gasket for that. But the amount of smoke is much smaller, I wouldn't think it would be enough to cause issues.

I think my O2 sensor is bad, the car is still idling quite rich, but the idle did stabilize finally (was previously doing the rhythmic surging routine). However the check engine light is coming on at idle. (The car is running great under load, the CEL goes off as soon as I blip the throttle). Regardless of simulated lean or rich conditions with the car warmed up, the O2 sensor is constantly outputting in the .8 voltage range. I think the O2 sensor may have been fouled when I first ran the car and the MAF was not getting power at all. The spark plugs I pulled out and replaced with new were very fouled.

The adventure continues. I've learned a lot about proper diagnostics and troubleshooting through all this.

[superj]

i don't know too much about putting a maf on an e30 but its working right? i know that back in the day, some people had problems with those

the e30 o2 sensor is a narrow band so if its not reading, or out of range, the ecu goes to a preset fuel trim map that actually works very well. maybe the chip is not seated properly, also?

[sienayr]

Thanks, so if I unhook the O2 sensor, and it still runs rich, sounds like that may indicate a potential issue with the MAF or chip? Will the preset fuel trim map work properly with the 19# injectors?

[superj]

it will run fine. i had a chip on a 535i afm in my car with the ford injectors and it ran fine when the o2 disconnected.

i would think its something with one of those but i have no experience with the maf, just what i read. i know when my son put his chip in with his 19lb injectors and his 535i afm, he had his chip seated incorrectly and his car wouldn't idle and ran horribly. we noticed it when we swapped the chip back to stock. one of the chips pins was bent and touching another pin

[msservices]

You can pressure test the entire engine just using low psi to find leaks. I’ve suggested this a dozen times on this forum and it’s been disregarded each time. I guess it required too much apparatus in the way of a few basic plumbing parts, but some of that apparatus can also be used to pressure test a cooling system when problems arise with those also.

[sienayr]

Closing the loop on this one. The vac leak from my original post ended up being the valve cover gasket, not the injectors. It was leaking on the high side so it made it look like the smoke was originating from the fuel injector area. So I got the vac leaks sealed, but still had the issues with low speed driving, lots of bucking and misfiring, rich idle with check engine light coming on at every stop.

Ultimately it was the injectors. The eBay site I bought them from had an incorrect xref part number listed. The injectors I bought were Bosch 0280150973. The site also listed 0280150943 as an xref part number so I bought them. After further research I found that 0280150973 injectors are listed for Buick V6 L36 motor, not Ford. So even though they look exactly like the yellow top Ford injectors they did not work well at all with the Miller MAF/19# chip. I got some different 19# injectors that someone had pulled from their M20 locally (Bosch 0280155746, the skinny yellow Ford kind), put them in and all of my woes are fixed. Car runs especially good now since I changed temp sensor, plugs, rotor, cap, fuel pump and fuel pressure regulator in an attempt to get the car running right. No biggie since all of that was original at 155K miles.

By the way, Miller support is just terrible. I got a few responses to my emails but it was very sporadic. Then he just stopped responding completely, totally left me hanging out to dry. And I was not asking obtuse, open-ended questions, I was giving very specific voltages, fuel pressures, etc. as I was testing just to get simple confirmation that things looked right or not, and they couldn't be bothered to help me with that. And they do not answer the phones.