Another Spark-plug diagnosis ;)

[BMWLOCO]

Car had been dying once warm. The only thing that is not new is the Fuel Pressure Regulator. If you search my posts, you'll see my diagnosis. These plugs are less than 500 miles old. Last night it stalled, this AM, it cranked right up. A few hours ago, I pulled a plug and it had some fuel residue and with a bad fuel smell.

Thanks in advance!

[spdracrm3]

wrong plugs to start with,those things are crap and cause all kinds of driveability issues. gap is to big for the ignition system on these cars,go back to single electrode copper core bosch plugs. im sure others will pipe up with the part #s

[LJ851]

^+1, get the right plugs in there. 4 electrodes my ass, M20 has two fingers up at those.

[BMWLOCO]

Will do ASAP..

Thanks and Sorry for putting a POS in the M20.. ;(

[jlevie]

While it is true that you are using the wrong plugs, I rather doubt they are the cause of the stalling. They may well be the cause of the sooting from partial misfires. More likely there are other problems that need to be addressed. Start by having a smoke test run on the intake and fix the leaks it reveals.

[e30leigh]

those plugs are for m54s and m52tu's. the issue with using those is the spark isnt deep enough in the combustion chamber

[BMWLOCO]

Got the single stem plugs and when I pulled the rest of the 4 prong ones, I noticed they all had fuel smell on them and still some sod deposits.

Put the new plugs in, and got a new FPR and all good so far.

A good test drive and nothing going wrong so far..

Thanks again...

[whodwho]

When some FPRs go bad the diaphragm ruptures and fuel gets sucked thru the vacuum hose, if you shake the old FPR does fuel come out the vacuum port?

[BMWLOCO]

When some FPRs go bad the diaphragm ruptures and fuel gets sucked thru the vacuum hose, if you shake the old FPR does fuel come out the vacuum port?

Some came out, but not sure if it was significant.

[dnguyen1963]

those plugs are for m54s and m52tu's. the issue with using those is the spark isnt deep enough in the combustion chamber

Funny...I went to Bavauto and search for spark plug for my '88 325i and along with the copper core are these plugs. I searched this forum and there were users using these Bosch 4-prong for years w/o any issues.

[e30leigh]

according to bmw data base etk parts cataloge bosch frp7dqp+ (bosch platinum 4 prong) isnt listed at all for m20 engines. ignore the heat range. thats the exact part number for m52tu and m54 ect. bmw only recomends the use of single electrode copper plugs for m20. early m20 also use different plugs then later ones. one have a longer reach then the other.

[jlevie]

Some came out, but not sure if it was significant.

Any fuel out of the vacuum port is significant.

[E30_fiend]

early m20 also use different plugs then later ones. one have a longer reach then the other.

I don't think this is accurate. I've used the same plugs in my 85 eta as I have used in my 90 iS.


Taylor