GVR-4 wont rev past 4500

jim69c · Oct 5, 2015

Hi all, i have a 1988 e39a vr4, car wont rev past 4500, when it gets to that point its like it hits a wall and dies hard, changing coils did nothing, changed ecu and fixed it for first run then same problem, help please

jay 2g · Oct 6, 2015

Could b plugged converter? Is it back firing or anything or will it just not go past? Could b a number of things honestly

97ebaygst · Oct 6, 2015

could be a boost leak causing fuel cut. run a boost leak test.

jimsgsx · Oct 7, 2015

Change your fuel filter. You are not getting enough fuel most likely and its super bad for your car. Check your plugs to see if they white and ashy. I had same exact problem, changed filtet and bam! Running perfect.

keveka2 · Oct 7, 2015

I'll second the boost leak is it like a stutter box or is it just runing like it lacks power

jim69c · Oct 7, 2015

Cheers for the input guys, ill try the fuel filter, how do i do a boost leak test? Its not like a stutter box or lacking in power, it has full power till it hits 4500 then dies hard like its been turned off

jim69c · Oct 7, 2015

And it has no converter, streight 2.5" from the turbo with a 3" streight through muffler

jimsgsx · Oct 7, 2015

Also it could be fuel sock.

steve · Oct 10, 2015

Some of the earlier non-US VR4's had dual board ECUs that are quite different from the DSM but still suffer from leaking caps like we do.

What ECU is in the car and have the caps been changed?
Do you have a datalogger?

When you say it dies hard, do you mean the engine dies or that it's like hitting the rev limiter and loosing power hard?

SasaniFab · Oct 10, 2015

maf sensor in good shape?

miliman13 · Oct 10, 2015

Another thread....... Must be a cold going around. op. Do you have a WB to see your ratio. You may be going super rich and not know it, it sounds and feels the same as fuel cut. A AFPR will give insight to the pressure of your fuel. Their is no point in changing parts unless your sure it's the cause.

jim69c · Oct 10, 2015

steve said:
Some of the earlier non-US VR4's had dual board ECUs that are quite different from the DSM but still suffer from leaking caps like we do.
What ECU is in the car and have the caps been changed?
Do you have a datalogger?

When you say it dies hard, do you mean the engine dies or that it's like hitting the rev limiter and loosing power hard?

Still running a duel board ecu, im looking for a single board eprom but hard to find here, it just dies, not loke hitting the limiter, if noticed it only dose it if i rev hard through the rev range if i ease through the rev range it goes all the way to rev limiter, if tryed 3 different ecu's and its still doing it so dont think its that, the exhaust it quite black and blows sooton the drive way on start up...... could it be running ritch..... could that be the problem?

steve · Oct 10, 2015

So the engine stops if you rev it hard.
Is there a check engine light and have you tried looking at the diagnostic port with a voltmeter to see if there are any stored codes.

Does it start easily?

Is the car all stock?
Have you checked the compression?
You need to run a boost leak test.
http://www.vfaq.com/mods/ICtester.html
http://www.dsmtuners.com/threads/boost-leak-test-how-to-with-boostpro-net-tester.169435/
http://turboboostleaktesters.com/how-to-boost-leak-test/
http://www.dsmtuners.com/threads/the-correct-way-to-do-a-boost-leak-test.95581/
http://www.dsmtuners.com/threads/boost-leak-sources.439060/

Without a datalogger you'll have to check the various sensors against the factory specs in the service manual.

jim69c · Oct 10, 2015

steve said:
So the engine stops if you rev it hard.
Is there a check engine light and have you tried looking at the diagnostic port with a voltmeter to see if there are any stored codes.

Does it start easily?

Is the car all stock?
Have you checked the compression?
You need to run a boost leak test.
http://www.vfaq.com/mods/ICtester.html
http://www.dsmtuners.com/threads/boost-leak-test-how-to-with-boostpro-net-tester.169435/
http://turboboostleaktesters.com/how-to-boost-leak-test/
http://www.dsmtuners.com/threads/the-correct-way-to-do-a-boost-leak-test.95581/
http://www.dsmtuners.com/threads/boost-leak-sources.439060/

Without a datalogger you'll have to check the various sensors against the factory specs in the service manual.

Cheers for the input, im running a evo 3 16g, external waste gate, s/s 2.5" exhaust and 3" intake pipe, apart from that its stock, it is running a vent to atmosphere bov from previous owner which i need to remove and plumb in but dont think that would cause my problem, ill do a boost leak and compression test, will let use no how it goes, a buddy coming to pull fault codes.

steve · Oct 10, 2015

What boost are you hitting?
Do these cars have the 510cc injectors or 450cc like a DSM?

jim69c · Oct 10, 2015

My boot controler is set for 13 and the gauge says 13, they have 450cc injuctors.

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GVR-4 wont rev past 4500

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