Bad MAF?? - Land Rovers Only

Greg M · 06-09-2006, 04:39 PM

Okay, I'm stumped. My engine has a bad idle and overall doesn't seem to run as great as it should. I have searched the BB and tried a few things, but i need some EFI guru help now. I recently rebuilt my engine, and I have new ignition parts.

When I start it in the morning it hunts for an idle speed. It cranks right up, ususally dies, cranks up again and will go from barely idle to 1500 or so RPM, back down to almost dying, back up to 1500 back down, you get the picture.
It idles okay when it has warmed up. So, figured idle control valve. Cleaned it and the seat - no change. Could definitely be bad, but let me continue.

I took a trip this weekend. The rig did fine, but when going over a pass at wide open throttle, the engine would cut out slightly. Figured maybe the TPS was giving fits. Later, I pulled over to get something out of the back and when I got back in, the EFI light was on. I didn't feel like screwing with it so i went on. But with the EFI light on (bypassing the system i assume) the engine was idling better, running better and no problems cutting out at full throttle. Hmmm.

So when i got back home i checked the TPS with an OHM meter and sure enough at full throttle it dances a bit on the meter. Ok, that explains the cutting out at full throttle. So I diconnected the battery to reset the EFI. Then, just for grins i disconnected the harness from the MAF. Guess what, it idles better and runs better with it disconnected. So, I figured the MAF was dirty so I cleaned the wires in the MAF, but it didn't do any good.

So any opinions at this point?

OkieRover · 06-11-2006, 07:25 PM

Thorough job.
Do you have anyone with a spare MAF you could try just for fun?

Greg M · 06-11-2006, 08:48 PM

Unfortunately no, but i can pick up a used one I guess.

Greg M · 06-14-2006, 09:20 AM

Anyone? Anyone?

Muddy Oval · 06-14-2006, 09:57 AM

you identified the TPS as having a problem but didn't fix it? It sounds as if the MAF is bad (running a K&N?), but with a known TPS problem I'd elimintate the known before throwing $ at it.

Greg M · 06-14-2006, 06:08 PM

Quote:

Originally Posted by Muddy Oval

you identified the TPS as having a problem but didn't fix it? It sounds as if the MAF is bad (running a K&N?), but with a known TPS problem I'd elimintate the known before throwing $ at it.

Well, I discovered the TPS at the same time, and yes, I am planning on fixing it however it only loses resistance at wide open throttle, so this is not the problem with the idle. I have a MAF on order so i will let everyone know.

Muddy Oval · 06-14-2006, 07:52 PM

Oh ok- I must have missed that part about only W.O.T. I've often seen them have several 'dead spots' on 'em. Other than the TPS, it does sound like a MAF problem. When you cleaned the wires, did you use electrical component cleaner? Throttle body cleaner or carb cleaner will ruin them...

Greg M · 06-14-2006, 11:03 PM

Quote:

Originally Posted by Muddy Oval

Oh ok- I must have missed that part about only W.O.T. I've often seen them have several 'dead spots' on 'em. Other than the TPS, it does sound like a MAF problem. When you cleaned the wires, did you use electrical component cleaner? Throttle body cleaner or carb cleaner will ruin them...

Yes, however it was acting up a little b4 that.

Greg M · 06-14-2006, 11:08 PM

Quote:

Originally Posted by Muddy Oval

Oh ok- I must have missed that part about only W.O.T. I've often seen them have several 'dead spots' on 'em. Other than the TPS, it does sound like a MAF problem. When you cleaned the wires, did you use electrical component cleaner? Throttle body cleaner or carb cleaner will ruin them...

Yes i used the correct cleaner, however it was acting up a little b4 that. Oh, and no K&N. Don't believe in them for off road use. What stumps me is that I have driven it every day and I have yet to have the EFI light come on. It seems to be getting worse especially when its cold - it really bogs down for about the first mile. This happens first thing in the morning or after its sat for a few hours during the day. Any chance the temp switch is leaning it out too much?

Muddy Oval · 06-15-2006, 09:17 AM

Temp switches are a common problem too... There are a lot of possibilities and the only thing you can do is test them. If you can't test them, then it's throwing parts at it which isn't usually cost effective. I'm guessing you don't have a good factory manual?

Greg M · 06-15-2006, 10:16 AM

So i decided to test a few things today. Got the volt tester out, pulled the ECU and guess what? I have a 14CUX!!

The original 13CU is sitting underneath it doing nothing. Got to love previous owners! BUT there is no code display.

06-09-2006, 04:39 PM	#1 (permalink)
Greg M Senior Member Join Date: Jan 2006 Location: Boise ID Posts: 219 Gallery: 0	Bad MAF?? New discovery! Okay, I'm stumped. My engine has a bad idle and overall doesn't seem to run as great as it should. I have searched the BB and tried a few things, but i need some EFI guru help now. I recently rebuilt my engine, and I have new ignition parts. When I start it in the morning it hunts for an idle speed. It cranks right up, ususally dies, cranks up again and will go from barely idle to 1500 or so RPM, back down to almost dying, back up to 1500 back down, you get the picture. It idles okay when it has warmed up. So, figured idle control valve. Cleaned it and the seat - no change. Could definitely be bad, but let me continue. I took a trip this weekend. The rig did fine, but when going over a pass at wide open throttle, the engine would cut out slightly. Figured maybe the TPS was giving fits. Later, I pulled over to get something out of the back and when I got back in, the EFI light was on. I didn't feel like screwing with it so i went on. But with the EFI light on (bypassing the system i assume) the engine was idling better, running better and no problems cutting out at full throttle. Hmmm. So when i got back home i checked the TPS with an OHM meter and sure enough at full throttle it dances a bit on the meter. Ok, that explains the cutting out at full throttle. So I diconnected the battery to reset the EFI. Then, just for grins i disconnected the harness from the MAF. Guess what, it idles better and runs better with it disconnected. So, I figured the MAF was dirty so I cleaned the wires in the MAF, but it didn't do any good. So any opinions at this point? __________________ Greg M 1987 RRC Rovers haven't made it to the far reaches of the Earth worrying about warning lights. Last edited by Greg M : 06-15-2006 at 10:02 PM.

06-11-2006, 08:48 PM	#3 (permalink)
Greg M Senior Member Join Date: Jan 2006 Location: Boise ID Posts: 219 Gallery: 0	Unfortunately no, but i can pick up a used one I guess. __________________ Greg M 1987 RRC Rovers haven't made it to the far reaches of the Earth worrying about warning lights.

06-14-2006, 09:20 AM	#4 (permalink)
Greg M Senior Member Join Date: Jan 2006 Location: Boise ID Posts: 219 Gallery: 0	Anyone? Anyone? __________________ Greg M 1987 RRC Rovers haven't made it to the far reaches of the Earth worrying about warning lights.

06-14-2006, 09:57 AM	#5 (permalink)
Muddy Oval Otherwise known as STEVE Join Date: Oct 2005 Location: Vermont Posts: 1,968 Gallery: 0	you identified the TPS as having a problem but didn't fix it? It sounds as if the MAF is bad (running a K&N?), but with a known TPS problem I'd elimintate the known before throwing $ at it. __________________ 2002 Freelander 2000 DII w/CDL 1967 SIIA 109SW Former Rovers 2004 Modded "S" Disco, R.I.P. 2004 G4 Disco 2002 Modded Freelander 1995 Modded Disco 1994 D-90 #8 1993 NAS D110 1990 Range Rover County 1973 SIII 88 1972 Range Rover 2 door

06-14-2006, 07:52 PM	#7 (permalink)
Muddy Oval Otherwise known as STEVE Join Date: Oct 2005 Location: Vermont Posts: 1,968 Gallery: 0	Oh ok- I must have missed that part about only W.O.T. I've often seen them have several 'dead spots' on 'em. Other than the TPS, it does sound like a MAF problem. When you cleaned the wires, did you use electrical component cleaner? Throttle body cleaner or carb cleaner will ruin them... __________________ 2002 Freelander 2000 DII w/CDL 1967 SIIA 109SW Former Rovers 2004 Modded "S" Disco, R.I.P. 2004 G4 Disco 2002 Modded Freelander 1995 Modded Disco 1994 D-90 #8 1993 NAS D110 1990 Range Rover County 1973 SIII 88 1972 Range Rover 2 door

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06-15-2006, 09:17 AM	#10 (permalink)
Muddy Oval Otherwise known as STEVE Join Date: Oct 2005 Location: Vermont Posts: 1,968 Gallery: 0	Temp switches are a common problem too... There are a lot of possibilities and the only thing you can do is test them. If you can't test them, then it's throwing parts at it which isn't usually cost effective. I'm guessing you don't have a good factory manual? __________________ 2002 Freelander 2000 DII w/CDL 1967 SIIA 109SW Former Rovers 2004 Modded "S" Disco, R.I.P. 2004 G4 Disco 2002 Modded Freelander 1995 Modded Disco 1994 D-90 #8 1993 NAS D110 1990 Range Rover County 1973 SIII 88 1972 Range Rover 2 door

06-15-2006, 10:16 AM	#11 (permalink)
Greg M Senior Member Join Date: Jan 2006 Location: Boise ID Posts: 219 Gallery: 0	So i decided to test a few things today. Got the volt tester out, pulled the ECU and guess what? I have a 14CUX!! The original 13CU is sitting underneath it doing nothing. Got to love previous owners! BUT there is no code display. __________________ Greg M 1987 RRC Rovers haven't made it to the far reaches of the Earth worrying about warning lights. Last edited by Greg M : 06-15-2006 at 10:01 PM.

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