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Cutting out at 4500rpm? updated and SORTED!


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16 replies to this topic

#1 Johnnyboy

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Posted 22 January 2006 - 04:53 PM

Hey guys and gals,
I've got a quick question for you, I've installed a 1988 RXII 1800 MPFI Turbo engine, with the 5 speed constant 4wd D/R gearbox into my 1983 Brumby (Brat).
It's been running perfectly, but suddenly last week, it started getting a savage engine cut out at 4500rpm, as in it seems the engine either lacks fuel or spark.
I had just installed a new Accel super stock coil and leads, plus regapped the sparkplugs. I've since checked and tested all of these, including going back to the old items, but still the cut out remains.
I get no error codes from the ECU and there is plenty of fuel getting through.
Something that spung to mind, is that i had to change the vacuum hoses on the wastegate actuator and solenoid, so i wonder if i got them round the wrong way and this has caused a overboost cut out to happen? I haven't swapped them around to the alternative, as i'm not sure if this may help destroy the motor if they are correct to start with. Does that make sense?
Does anyone have any suggestions or diagrams of how the vacuum lines connect between the wastegate and solenoid?
Any help or suggestions would be great

#2 calebz

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Posted 22 January 2006 - 04:58 PM

Fuel cut on the 87+ (USMD) is a function of voltage from the MAF..

Do you have a boost gauge? what sort of levels are you running when you get fuel cut?


One thing you could do to rule out the wastegate actuator and solenoid, is to take the solenoid out of the picture .. Kinda useless except at altitude anyway.

Just run a vacuum line from the compressor housing to the wastegate actuator (will require about 8 inches of vacuum hose).

This will set you to wastegate boost ~7psi.

Romp the crap out of it and report back.

#3 Johnnyboy

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Posted 22 January 2006 - 09:37 PM

ok, i installed a boost gauge, it shows no more than 8 at 4500 rpm.
I tried your idea, it made no difference, so i'm guessing it's not the overboost cut out.
I'm now thinking it's an earthing problem, i need to perhaps attach more earth lines and recheck the earth on the ECU.

#4 subiemech85

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Posted 22 January 2006 - 09:44 PM

this may help: http://www.ultimates...light=dead zone

#5 Johnnyboy

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Posted 22 January 2006 - 09:56 PM

Ok thanks Subiemech85, I'll check the TPS out as well.

#6 Johnnyboy

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Posted 25 January 2006 - 06:46 PM

Ok, i've checked the TPS, it's ok, I cleaned the MAF and I've made sure the system is well earthed.
I've got a fresh tank of 98 octane and i happen to put some injector cleaner in while i was at it. The fuel filter is clean.
Now the damn thing won't run well at all. It won't even idle and if you try to pump the gas it has a bad hesitation and backfires somewhere in the engine.
If you disconnect the MAF, it idles fine, but still has the hesitation and backfires etc.
The timing seems to be fine and the ignition coil, spark plugs and cables are new. There still appears to be plenty of fuel pressure.
I checked the thermo sensor, I've cleaned it contacts. After the engine warms up without the MAF connected, it idles where it should, so does that mean the thermo sensor is working ok?
Have i screwed the MAF by cleaning it with spray contact cleaner? the wires look fine and it appares to be ok when tested with my multimeter.
I get the error code 33, which seems to be the Knock Sensor, but it tests fine and to be honest, I've had that error before and the engine was running fine, plenty of get up and go.
Any ideas worth checking?

#7 ballitch

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Posted 25 January 2006 - 08:03 PM

i dont know for sure but i thought you weren't supposed to clean or mess with the older maf sensors because of some reason. thats vague isnt, sorry, but im sure someone with more learnin' will chime in.



~Josh~

#8 calebz

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Posted 26 January 2006 - 12:09 AM

Sounds like you MAF was toast to begin with. Time to hit the junkyards!

If it makes you feel any better, I am on my 3rd or 4th MAF in my wagon.

#9 Johnnyboy

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Posted 26 January 2006 - 01:04 AM

ok, well i replaced the MAF, now it idles fine and runs ok, but just no power.
As in you put your foot down, the turbo boosts up to 7PSI and it accelerates like a three legged dog... with 3 legs tied behind it's back. REALLY bad.
Shouid i be replacing the TPS just in case?

#10 4WDFrenzy

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Posted 26 January 2006 - 03:40 AM

Double check your spark plug leads. Just in case they are in the wrong positions on the distributor cap. By the way you have described it, it almost sounds like a spark timing issue, especially if it is backfiring. Did you remove the distributor at all? Advance or retard the ignition timing?

Patrick

#11 Johnnyboy

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Posted 26 January 2006 - 08:56 PM

Leads seem to be ok..
It runs okish now, nice idle and revs very freely..

Only thing is, when you go out for a drive, it just revs slowly and pulls slowly.. like it was pulling a huge trailer or something. Foot to the floor and getting no where fast.

No error codes and the boost gauge is reading up to 8 PSI boost. The Turbo is working hard, it gets plenty hot enough.

Any ideas on this one?

#12 tizzle

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Posted 26 January 2006 - 09:49 PM

I have a similar problem. I just installed a brand new head. The car ideals beautifully, but when I go to drive it, i does not want to accellerate. I think it has to do with all the electrical connections I messed with at the same time (applying dialectric grease)

I have a possible crank angle sensor code. Maybee I messed something up with the timing belt even though I was pretty meticulous about that.

--also the plug wires just do not want to sit snug and happy on the distributor or coil, so I might change those ( year old )

--Todd

#13 Ross

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Posted 26 January 2006 - 11:48 PM

To start with, get that 98 octane out (unless you got high comp ratio pistons in?), it only needs 91 - anything higher and you will loose power. I can notice a difference between 91 and 95, so i'd say 98 would make quite a difference.

Have you checked for old stored error codes as well as current ones?

#14 Johnnyboy

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Posted 27 January 2006 - 12:14 AM

Ok, i just got used to running a higher octane, cos the previous engine i had was a twin card EA81. doh!
I'll drain it out and use it elsewhere, I'll try a tank of 91.
I haven't looked for the old codes yet, but I've got the Knock Sensor comming up again, so i think I'll replace the knock sensor and see how that helps as well.

#15 hooziewhatsit

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Posted 27 January 2006 - 12:38 AM

Leads seem to be ok..
It runs okish now, nice idle and revs very freely..

Only thing is, when you go out for a drive, it just revs slowly and pulls slowly.. like it was pulling a huge trailer or something. Foot to the floor and getting no where fast.

No error codes and the boost gauge is reading up to 8 PSI boost. The Turbo is working hard, it gets plenty hot enough.

Any ideas on this one?


pull your plugs and see what they look like. If they're white, you're either running uber-lean, or you don't have spark in the cylinder. You could also *carefully* pull each plug wire off the disty one at a time and see if changes the idle at all. If it doesn't, that cylinder isn't firing, and will make it a slug.

A certain someone I know, who shall go un-named, didn't get two injector plugs back on properly after doing some work... car ran just like you described, until they were plugged back in ;)

oh yea, plugs should be 1, 3, 2, 4
front
2 1
4 3
rear

*when I say carefully, you don't want to shock the crap out of yourself :)

#16 Johnnyboy

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Posted 29 January 2006 - 10:57 PM

Well, it's a runner again.. in fact it's going better than ever, I guess it just needed to be fussed over and get a few new "go fast" toys.

Today, i strenghtened the rear diff mount with 6 mm steel at right angles.
Helps to keep it strong and give it some "impact" strength.

I also made a duct from the inner front "high beam" light (removed the light) through towards the back of the engine bay, to help cool the turbo and get a bit of fresh air to the back for the air cleaner.
You can see in the pics i've attached, i've used a internal "snorkel", taking the k&N filter (pointing away, towards the firewall) up to where the spare wheel should sit. (My 28" wheels don't fit there any more) i've used that snorkel for some time, i can easliy drive through water over the bonnet with no problem.

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#17 subiemech85

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Posted 01 February 2006 - 01:10 AM

I had the cut out issue until the idle adjusting screw fell out, then it wouldn't idle, but also wouldn't cut out

I get the low power issue when I run E85, but I have gotten used to it
until I get bigger injectors :drunk:




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