M20 will not rev past 3,000rpm

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Re: M20 will not rev past 3,000rpm

Postby Yoshi » Fri Apr 25, 2014 11:35 am

Late models, I could easily do without taking off the intake. Early models... I think I took off the FPR and slid it out front ways. Wound up hitting the thermostat housing or something... But yea. Never took off intake.
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Re: M20 will not rev past 3,000rpm

Postby blasphemy101 » Sun Apr 27, 2014 4:06 am

What's different from early to late model for the fuel rail? I have an early model, but it's an '87 is, so it's kind of a weird, in-between late and early model setup

Keep in mind, if your injectors are original or rebuilds, you may end up having to remove the manifold anyways because the caps on the tips of the injectors have a habit of staying in the manifold when you pull them off.
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Re: M20 will not rev past 3,000rpm

Postby M20_fever » Sun Apr 27, 2014 4:13 am

I'm pretty sure the fuel rail changed at the same time the cooling system did, so '88 I think. Which cooling system does your car have? Old style right?
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Re: M20 will not rev past 3,000rpm

Postby ivprodigy » Sun Apr 27, 2014 5:20 am

It's the new style. Looking at older units the fuel rail is thinner and the bolts holding it in place are easier to get to.
I'll take the manifold out it should be easier.
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Re: M20 will not rev past 3,000rpm

Postby Ryki » Mon May 12, 2014 11:52 am

I seem to remember Yoshi mentioning a resistor in the line (cps maybe) that would cause you to not rev right. Thoughts?
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Re: M20 will not rev past 3,000rpm

Postby blasphemy101 » Mon May 12, 2014 5:25 pm

Since I'm installing head studs and new injectors this week, I'll document the process and post it in this section. It should help us clear up any discrepancies.
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Re: M20 will not rev past 3,000rpm

Postby ivprodigy » Wed May 14, 2014 10:50 pm

Sorry I've been busy with other stuff around the house.
The resistor I think you are referring to is in the VR+ jumper.
I did take out the intake to get to the injectors (it's really quick and it's probably the easiest way to get the injectors out.

I didn't actually take out the injectors. It didn't look like the are leaking as they primed ok (one squirt when priming and nothing else)
Yoshi I think you are right and my tune is probably the culprit.
Putting everything back together this week and I'll be talking to ams sports which seems pretty reputable to get them to tune it
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Re: M20 will not rev past 3,000rpm

Postby M20_fever » Thu May 15, 2014 3:40 am

must have dyno vids!
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Re: M20 will not rev past 3,000rpm

Postby Yoshi » Thu May 15, 2014 3:35 pm

Add one to the "yoshi was right" list. up to like 8 now lol.
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Re: M20 will not rev past 3,000rpm

Postby ivprodigy » Wed May 21, 2014 2:10 am

Right on Yoshi!

So it started hailing tonight so I took the chance to dig into the E30 finally.
I came across a couple of curious things...
First it was this:
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I didn't look too closely but I think its from cyl 1 which may be the cause of some of my problems...
The wires are Bremi, do you guys think I can fix it or is it a one and done?

I also discovered a hole (I noticed it during the assembly but didn't think it'd be an issue) in the head that is the likely culprit of an oil leak that i thought may be coming from the head gasket... the bolt that holds the timing belt cover treads in there but it looks like the oil seeps through and leaks down the front of the engine. There isnt anything else (aside from the head gasket that could be the cause)
It looks like the PO tried patching up the hole with what I could guess is JB weld. Is there anything else I can do to close up the hole?



Lastly, I was checking the tension of the timing belt and it seems that the one side may be a little loose while the other (side of with the pulley) seems fairly tight. Is that normal or should I re-do it while I've got everything out?

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Re: M20 will not rev past 3,000rpm

Postby Yoshi » Wed May 21, 2014 11:41 am

Get new wires. That may be what's causing your breakup. Never skimp on M20 ignition wires. Them damn bav auto "upgraded" ones are shit too. Just get a good OEM replacement.

The head, Ideally you should take it and have it tig welded. I'd just JB weld it from the outside and be on my way but keep an eye on it. Won't last forever though.

The tension on the belt is normal. The way the motor moves, that other side will always have tension. It's ok for the other side to have slack.
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Re: M20 will not rev past 3,000rpm

Postby M20_fever » Tue May 27, 2014 4:02 am

For sure replace those wires. The heating/cooling of the head will prevent anything but a good tig weld from sticking. I would replace the spring on the tbelt tensioner to be safe, and confirm it was installed right.
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Re: M20 will not rev past 3,000rpm

Postby ivprodigy » Tue Jul 29, 2014 3:08 am

Hey folks
It's been months since I've come to the board and even looked at my car...
Since I've had a hard time getting my ms to work right (probably something I didn't do right) I am hoping that I can go back to a semi stock setup without too much heartache.
Will I be able to buy an AFM and a stock ECU to get the car running on the stock setup?
If so, will I need anything else to get the car started?

Thanks

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