Boost Gauge stuck on zero

[GMCinMich]

Wondering if anyone knows where the turbo boost sensor is located on an 87XL (8V92). Prevost wants $170 for a sensor kit. I have replaced my manifold gaskets and the turbo seems okay.

[MangoMike]

GMC,

Glad you posted and welcome to the board. Hopefully one of these crank heads has an answer for you. I would also post on prevost-stuff.com and if no response http://www.busnut.com/bbs/messages/1...tml?1147145204.

Mike

[Jon Wehrenberg]

I don't have my 8V92 coach anymore so I can't send a picture, but the sensor is slightly hidden from view on the RH side (facing the engine from the rear of the coach) of the fuel block (the rectangular "can" mounted at the top center of the engine) hidden slightly by the turbo inlet pipe.

It is a black plastic device about 1 1/2" by about 2 1/2" held on by a single screw and nut and it has a small diameter hose connected to it (pushed on).

You can replace it yourself in about five or ten minutes with a screwdriver. The last one I bought I got from Detroit Diesel for about $80. Before you buy a new one verify the tubing is pushed on and is not cracked or leaking.

In the attached photo the sensor is located as described above and if you look at the picture it is in the area under the rusty turbo inlet pipe on the right, immediately to the right of the rectangular box with the red cover behind the Racor. Hope this helps.

[lewpopp]

I was noticing my boost guage while coming up to J'ville. I read about 5 during normal driving. What should it read?

[Jerry Winchester]

Depends on how well those truck drafting lessons went

GMCinMich,

Welcome to the board. If Jon doesn't come up with a photo, I will take a pic of mine on Wednesday and post it for you.

JW

[Jon Wehrenberg]

Lew, with a tailwind (that is airplane talk) on level ground (holding the same altitude, more airplane talk) about 5 sounds reasonable. I think anywhere between there and 7 is where it would be expected to be at 55 knots (63.25 mph for non pilots).

[Jon Wehrenberg]

GMC, We will need Jerry to post his pictures since I don't have an 8V92 to photograph any more.

This will be a good test because he has been trying so hard to out bling me, we will all see if he has his engine clean and detailed or if all his spare time went into lead lights.

BTW, if you have not figured it out by reading the blather that goes on here there tends to be a certain amount of ball breaking. Take it with a grain of salt because most of the clowns on this forum are nothing more than trouble makers. Except for me. And Roger who will be delivering my new M3 anyday now.

[GMCinMich]

Thank you for the interest in my dilema.
I have located the fitting on the left side of the blower inlet and the plastic line. Removed the L shaped floor access under the bed (with great difficulty) and traced the line forward. Went into the steering gear access area and located the other end as it goes into a conduit up to the dash. Got under the dash and noticed a small plastic line connected to the boost gauge.
The gauge center is zero and the needle can go plus or minus...not sure why it would go minus. My conclusion at this point is that 87's must not use a sensor.
The turbo spins freely although I did remove a small bees nest on the inlet screen. Going to check the line for leakage with alittle pressure. It could be my gauge is tired.

[Jon Wehrenberg]

If your coach does not need a sensor then it does not have DDECI.

If it does not have DDECI why would they try to sell you the kit? Hmmm.

GMC the computer coaches DDECI were introduced mid year 1987 and the way to spot a DDEC coach back them before folks started changing headlights and tailights to keep up with the Jones was the turn signal and brake lights were rectangular.

[GMCinMich]

I called Prevost parts in Elgin..they didnt ask me if I had DDEC1. This must be why my accelerator pedal seems to require alot of pressure. Gerry