wont rev past 3k Rpm

mjbrox

Well-known member
Jun 30, 2008
1,705
26
Golden CO
On the way home from at little off road trip my D1 would'nt rev past 3k RPM. That obviously made the highway drive back home a bit annoying. I tried reving it in neutral and the most I could get was 3200 RPM.

I dont have a CEL

any thoughts?
 
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Swedjen2

Well-known member
Sep 12, 2018
376
61
California
1) You are a creative speller.
2) Sounds like a mechanical issue with the throttle cable and/or anything related to it. Pedal, throttle body, etc. But I'm just throwin' darts.
 
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discostew

Well-known member
Sep 14, 2010
5,561
255
Northern Illinois
Make sure the air inlet is clear and the filter isn't wet. Then scan the thrttle position voltage. Just watch it while you sweep it from closed throttle to wide open. Then 3rd check your fuel psi.
 
Apr 20, 2004
6,630
83
Lexington, Va
Check your wiring also to the CPS. They get brittle and I have seen several ground out against the block and cause a similar issue.... Obviously a weak pump will cause it as well but I am betting you will find a wire exposed.
 

mjbrox

Well-known member
Jun 30, 2008
1,705
26
Golden CO
Check your wiring also to the CPS. They get brittle and I have seen several ground out against the block and cause a similar issue.... Obviously a weak pump will cause it as well but I am betting you will find a wire exposed.
you know....... Just before it i was rallying down a super bumpy road and I could hear something flopping around in the motor compartment.

I had to go do civilized shit as soon as I got home so I didnt even pop the hood.

Thank you for that tip, ill go poke around shortly
 

jymmiejamz

Well-known member
Dec 5, 2004
5,672
146
32
Los Angeles, Ca
You can de-pin the crank sensor connector one wire at a time and just put a 6" section of heat shrink tubing on the wires. It always seems to happen near the sensor in my experience.
 

best4x4

Well-known member
Mar 1, 2015
451
12
Beaumont, TX
I had this two times on D1's (a 95 & 98). For me each time it was a catalytic converter breaking free inside the housing and clogging the exhaust pipe. Engine would bog and not go past 3.2K. On the 98 I was able to blow the chunk out, but the 95 wouldn't so I had to lower the Y pipe, and bang the chunk into smaller chunks before it was free and clear.

Might not be your problem, but you can crawl under your D1 and bang on the Y pipe cat's They should not rattle. The other clue I had on the 95 D1 was small silver flakes flying out the exhaust tip.
 
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Swedjen2

Well-known member
Sep 12, 2018
376
61
California
I had this two times on D1's (a 95 & 98). For me each time it was a catalytic converter breaking free inside the housing and clogging the exhaust pipe. Engine would bog and not go past 3.2K. On the 98 I was able to blow the chunk out, but the 95 wouldn't so I had to lower the Y pipe, and bang the chunk into smaller chunks before it was free and clear.

Might not be your problem, but you can crawl under your D1 and bang on the Y pipe cat's They should not rattle. The other clue I had on the 95 D1 was small silver flakes flying out the exhaust tip.
"and I could hear something flopping around in the motor compartment."

Getting warmer.
 

robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
This is interesting as i can also not get it to go above 3.2k at driving speed but in neutral itll rev up just fine. Is this related or something different? This mostly happens ascending hills/mountains. Ill sit at 2.4-2.6 and then ill need to push down to the floor to get it to go above 3k and thats usually delayed.
 

mjbrox

Well-known member
Jun 30, 2008
1,705
26
Golden CO
I had the smart idea to throw a MAF from my brothers disco. It ran great, so I bought a couple of MAFs but my issue still remains. However when the engine is cold it seems to run better. But great news!!!! I have CEL (P0340). I just looked at the CPS and the wire seems in tact and still has the factory plastic shield

Could I just need a new CPS? it looks relatively simple
 
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robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
I had the smart idea to throw a MAF from my brothers disco. It ran great, so I bought a couple of MAFs but my issue still remains. However when the engine is cold it seems to run better. But great news!!!! I have CEL and it is something to do with the Cam Shaft Position Sensor. I just can figure out exactly where these exposed wires might be
Funny enough, I have a new MAF on the way and crank shaft position sensor in my stock. My higher elevation mpg is rough so curious if a different MAF improves it.
 

best4x4

Well-known member
Mar 1, 2015
451
12
Beaumont, TX
When you look up the P0340 fault it basically tells you that either one of the sensors cam or crank are not working together properly or are out of range.

I recently worked on two D1's that had been sitting for years (98 & a 99 D1). Both would not run! The 99 had a crank sensor harness which was totally missing the insulation and it was shorted out above the sensor. The 98 I simply crawled under the D1 and found the crank position sensor unplugged!

Both had P0340 faults and neither had any issues with more $$$ cam sensor.

Both fired right up and the P0340 faults never returned once the repairs were made to the harness and the other was fully plugged in.
 

discostew

Well-known member
Sep 14, 2010
5,561
255
Northern Illinois
I'm seeing it as camshaft position A fault. If the camshaft signal is missing you have a 1 in 5 chance the multipoint fuel injection will be timed right on start up. If I was working on this truck I would be looking at the wire harness to that sensor because they do get damaged by the pullies and belts if it's not secured. Also they get oil soaked and exposed near the sensor itself. If all that checked out I would spin the engine with the sensor out and make sure the magnet is still on the cam gear.
Cost of the part is now the way we decide what to buy next? I don't buy shit unless I know what that part is supposed to be doing and knowing that it's not doing that
 

mjbrox

Well-known member
Jun 30, 2008
1,705
26
Golden CO
. Also they get oil soaked and exposed near the sensor itself. If all that checked out I would spin the engine with the sensor out and make sure the magnet is still on the cam gear.
Its the Camshaft sensor is definitly soaked in oil. Next up i need to locate the crankshaft sensor

But first my wifes BMW is broken......
 

mjbrox

Well-known member
Jun 30, 2008
1,705
26
Golden CO
I drove it some more today. When it was below 185F it ran great. above 185 and it stopped reving at 4k.

How can i confrim the CPS is still good?