99 Grand Cherokee input turbine speed sensor

A coouple of guys in UK obviously had the same problem...

Very frustrating...in the end they set light to it and drove it into Glasgow airport.

damn jeep

I have never heard of a speed sensor on a Turbo ( I could be wrong of course!). The reasons are that Turbo speed has little to do with the "amount" of air being "pushed" into the engine. The amount of air is affected by temperature, height above sea level, the ambient air pressure etc etc., which is why a speed sensor is rarely needed....

Also, most Turbos get very hot and sensors generally do not like that!! Turbos can go beyond "red hot".....

Read thru the following:-

A blocked air filter or missing air filter will cause engine temperature problems.

A Turbo engine must be run at tick over for at least a minute before switching off the engine, due to the latent heat in the Turbo casting....the oil must cool it down....engine off = no oil flow. If you do have a turbo speed sensor the heat will do it no good....

Mostly there is an Air Volume sensor (hot wire method) that measures the amount of air going past it and informs the computer, these get dirty and as far as I am aware, cannot be cleaned. Modern engines you only need to change out the hot wire element, older versions (99 would be old) need the complete unit to be replaced.

VW had a lot of problems up to about 2003 with them getting dirty. The unit cost €200 or so at that time + installation costs. The air filters have been improved since then to take out even smaller particles from the air......

Most of these sensors are made by one company for VW, Mercedes and BMW etc.. your sensor might be from the same company. But don't ask, I haven't a clue what the company is called, but changing a VW one out for a Mercedes version gave like 40 BHP more for the VW 2.0 TDI motor and washed out the guarantee!!! They must look very similar......even identical I would guess.....

I got mine, on my 2002 Sharan, replaced under guarantee after having it go in the mountains of north Italy while towing a heavy caravan!!! I lost 40% of my BHP.........!!! Starting on an incline cost me half a clutch each time.....

My follow on cars (a Touran & a Mitsubishi Grandis, both with the VW 2.0 TDI motor) have not exhibited the problems as of now......

This is about automatic transmission sensor and not about turcharger sensor.

This sensor measures the speed coming from torque converter's turbine which drives the input shaft of the gearbox. So you should find it on the transmission. Second time in a year for a 8 year old box makes me think of corroded contact. Check all connectors for corrosion.

BTW To prevent corrosion of connectors never wash your powertrain and wiring with high pressure jet , even if it looks better after; i'd rather keep it look dusty but without moist or water in connectors.

Randolph

Thanks for the important correction, it made absolutely no sense before.

This shows that people should proof read much more carefully!!!

Hello again

You can also buy a good manual like the Haynes Jeep Grand Cherokee manual

I guess it got all you need to know. At least the pictures of where to find the components in the car.

Best regards

Randolph Toom

Your answer is this... As I had a similar prob. Your Jeep was made in Canada, ( in fact its made just up the road from me ) we use metric system and the conversion does not work electronically linear to Imperial. The sensor is replacable with on old Jeep version. circa 1984ish. Buy one at a wrecking yard and all will be well. Trust me! ash