89-91 Diesel K5 question

[AJMBLAZER]

So...they changed a few things in the 89-91 trucks that had gas motors. Anything change in the diesel trucks?

My main question right now is just the speedo. I know in '89 they went to the VSSB and did away with the speedo cable. Did they do this with the diesel trucks too? There's no computer soooo...how did they do it?

I don't even have it yet and I've got a zillion little questions.

 

[6.2Blazer]

It has the VSS and an ECM (computer). You can hook an older OBDI scan tool up to it and read codes and such, but in general the parameters the computer controls are extremely limited as compared to a similar year gas K5. I know my '90 would get a "check engine" light and show a code for the EGR when it was sticking. Think it reads the vacuum (from the pump), controls the speedo, and TCC...but it's been awhile since I really looked into it. Obviously there is no direct feedback to the engine operation, though if the EGR sticks it's like you lost 40 HP.

 

[AJMBLAZER]

Ohhhh fun.

So if I wanted to put 33's on it and recalibrate the speedo...are there chips out there just like there were for the gassers?

 

[tRustyK5]

89 is still mechanical. 90 was the first year for the VSS crap.

Rene

 

[kennyw]

This one does have a check engine light that pops on from time to time... but like it was said, it is just a monitor with no feedback or control. A J code intake would eliminate the problem with an egr.

And as Rene said, it should have a speedo cable since it is the last year for that. It does have the NP241 rather than the NP208 as well.

 

[AJMBLAZER]

Cool. I have my paperclip waiting to check the codes!