'97 D90 doesn't want to start in the morning

[BMGmotors]

K so the priming thing didn't make the car start. Were you saying in that case I need a new fuel pump?

 

[BMGmotors]

K so I had a check engine light on so I took it to get diagnosed and the guy told me there's a fault code for the potentiometer, with that being said can anyone give me any more suggestions? The fuel filter and pump are new, have added fuel system cleaning additives twice, new Bosch plugs and wires, new oil and air filters, I fill the tank w/ premium only now.

 

[Disco Mike]

Before you start a tune up, you might want to fix your actual issues. First clean your t/body and IAC, the 2 most common high idle problems, then replace your fuel filter and plan on replacing your fuel pump after verifying that you have no fuel pressure in the rail before trying to cold start it. There is a valve in the fuel pump that fails causing the gas/pressure to bleed off over night which then makes it hard to start. If you want to verify the pump issue, send me your number and I'll walk you thru what to do.
Know go thru and do my full service list to get that rig up and current and have fun wheeling.

1 Oil filter, K&N 3001 or Mobil 1- 301
1 Factory air filter
6 Qts. of engine oil
2 feet of 3/16th vacuum tube
2 feet of 5/16th vacuum tube
6 Qts. Of Vavoline’s high mileage ATF
7 Qts. of 80/90W synthetic gear oil, 85W/140 for HD use
3 Pints of Vavoline’s DOT 4 Brake fluid
4 Qts of synthetic ATF fluid for your power steering
2 Gallons of the best green coolant
1 Bottle of Lucas Power Steering additive
1 Bottle of Lucas Transmission additive
1 Can of Spray Carb. Spray
1 Can Of Brake cleaner
8 Spark Plugs, I use Bosch Platinum Plus 4's
1 Set of Magnacor or STI 8mm plug wires
1 Serpentine belt
2 Bottles of SeaFoam gas additive
1 T/Stat
1 bottle of WaterWetter or Purple Ice
Hoses and belts, as necessary

60,000 Mile Service or Major Service for High Mileage Used Vehicle just purchased

Bleed the brakes
Flush and change the power steering fluid adding one bottle of additive
Service the tranny adding one bottle of additive
Change the coolant and t/stat
Do an engine flush before changing the oil
Do an induction cleaning
Clean the throttle body
Add fuel additive to full gas tank
Change both of the diffs fluid
Change the t/case oil
Replace the plugs and wires
Replace the air filter
Lube all the drive shaft grease fitting including the 2 slip shafts
Do full inspection of brakes, hoses, bushings etc.

Hopefully I didn't leave anything out.

 

[BMGmotors]

I have around 40-45 psi in the fuel rail on cold start.

 

[BMGmotors]

Thanks Disco Mike for the service list, I really appreciate your taking the time to type that up, Especially since I just got this truck and I'm only 18 so I'm not quite sure what I'm dealing with. My first car was a Triumph TR6, so all this engine management system and GEMS engine stuff is new to me. I love my D90 though so thanks for helping me stay on the road!
Best Regards,
BMGmotors

 

[BMGmotors]

The new potentiometer did the trick!

 

[Disco Mike]

Before you do a tune up and other maintance, you need to check your fuel pump. There is a valve in the pump that is supposed to get fuel pressure in the rails over night, when this valve leaks down, you have no fuel pressure to start on.
Try priming the pump by turning the key to the second position for 4 to 5 seconds, then back off. Do that 3 time and then try and start your engine, if it starts, there is your problem, a bad pump assembly.

 

[antichrist]

The new potentiometer did the trick!

For future reference sometimes you can have a code without the CEL being on, so if you're having running issues, it's always a good idea to check for codes. That one may have been there all along.

On the starter issue you mentioned, I doubt it's an electrical supply issue. More than likely the bendix is gooped up. You could just pull the starter and clean it up and lube it with some very light machine oil.

 

[Disco Mike]

Besides a tune up as mentioned, to correct the idle issue, clean the t/body and both the IAC, idle air control valve as well ass the hole in the manifold that the IAC plunger fits into.
The start issue can be tested for and verified, send me your number and I'll walk you thru what to do.