limp mode??

[Rickie3]

Yesterday I installed a EGR blanking plate, and I also removed the the MAF sensor and gave it a good spray of carby cleaner and re-fitted, anyway went for a drive and my bus ran sweet as, oh yea its a 2000 GU wagon with the 3Litre direct injection donk, anyway today went down the town and on my way home the engine went into limp mode and crept up the hill, so I backed right off the throttle and hit the throttle again and away she went back to full power, would fitting the blanking plate have anything to do with it going to the limp state? before I actually did the plate ive had a small issue like a flat spot when I put the gas down what causes this flat spot? any help appreciated

[mudski]

If you don't have a dawes valve installed the EGR plate will be causing the issues I reckon. Also carby cleaner is not the best thing for cleaning the maf. Supercheap and the likes actually sell a maf cleaner. Remove the EGR plate and see what happens.

[the evil twin]

EGR faults in a CRD won't trigger limp mode, they just latch the check engine light and store a "P04nn" fault code.

Dunno about the pre '07 ZD30's like yours, but I would have thought it a tad odd. If you had flat spots before it could be throttle/engine sensor related.

Mudski's right tho, you could try taking the block out if it's easy enough (it's a huge PIA in a CRD)

[Mud Gecko]

When you block the EGR it raises the MAF voltage by around 0.2V to 0.4V. This is why you are suddenly getting limp mode, you can either lower your max boost or get a voltage modifier to trick the ecu.

[the evil twin]

When you block the EGR it raises the MAF voltage by around 0.2V to 0.4V. This is why you are suddenly getting limp mode, you can either lower your max boost or get a voltage modifier to trick the ecu.

OKaaaay, I'll bite.
If thats the case, why doesn't everyone need a "voltage modifier" ?

[kevin07]

OKaaaay, I'll bite.
If thats the case, why doesn't everyone need a "voltage modifier" ?

silence I kill you

[the evil twin]

silence I kill you

ROFL... hiya mate,

I'm curious is all. It could be another Di thing that us CRD jock's thankfully don't encounter.

[Covo71]

Hi mate, I have done most of the NADS over the last couple of weeks. When I put plate in a drive around to see what happens it went for a few days and then started to go in to limp. Installed Dawes and needle valve and all is ok again.

[threedogs]

When you block the EGR it raises the MAF voltage by around 0.2V to 0.4V. This is why you are suddenly getting limp mode, you can either lower your max boost or get a voltage modifier to trick the ecu.

I cant see how blocking an exhaust recycling pipe your MAF receives extra volts ??

[Mud Gecko]

I have a Di, according to the Nissan manual, MAF voltage should be 1.6v-2.0v. With a blocked EGR and no modifier, MAF voltage at idle is 2.2v-2.3v. Without my modifier and running 18psi of boost I will get limp mode at 2500rpm and just under 3000rpm @ WOT in 3rd and 4th. Limp mode is a combination of high boost and high MAF voltage. Usually if you go over 3.98v under 3000rpm you'll get limp.

With my modifier, I have tuned my MAFv at idle to 1.7v-1.8v. I no longer have that "fuely" smell at idle and I can tune out limp mode by raising or lowering the MAF voltage around those limp points.

If you don't believe me there is plenty of info on the "other" site, lots of guys doing it now.