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Kalamykid
Kalamykid, Shop owner/ Tech.
Category: Car
Satisfied Customers: 3908
Experience:  I HAVE OWNED MY OWN SHOP FOR OVER THREE YEARS. I HAVE THE TOOLS AND SOFTWARE TO ANSWERE ALMOST ANY Q
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1998 tahoe: of starting fluid and it will crank and run

This answer was rated:

I have a 1998 tahoe and the problem is that it will not crank. you can spray a swiff of starting fluid and it will crank and run. sometimes it will continue to crank for the rest of the day. i changed distributor and checked fuel pressure it has 60psi.

Kalamykid :

DO you have a digital volt meter to do some testing with?

Kalamykid :

You will also need a paper clip.

Customer:

okay

Customer:

what do i need to do

Kalamykid :

The first thing I need you to do is tahe a papaer clip and slide the paper clip into The tps plug along side the gray wire. Then set your meter to dc volts and with the ignition switch on see what the voltage is for the gray wire.

Customer:

okay give me a minute

Kalamykid :

ok

Customer:

.5 volts but the truck is cranking right now

Kalamykid :

From the information yu have posted I would have to say the tps is sending the pcm the wrong information when the engine will not start. this can be due to a bad wire to the tps, a bad tps itself, or the pcm.

Kalamykid :

One thing i see that is a little off, is the gray wire shoudl have 5 volts, not .5. What did you have your meter set to?

Customer:

my bad it was 5 volts

Customer:

does the tps have anything to do with the spider

Kalamykid :

yes if the tps tells the pcm that you have your foot on the floor then the pcm will shut the ijectors off to "clear flood mode".

Kalamykid :

There are ithree wires to the tps, the gray 5 volt refferance wire, a black ground, and the third wire should have .5 volts at close throttle and shoudl go up top 5 volts at wide open throttle.

Customer:

all that checks out okay

Kalamykid :

But the engine did start on its own corrct?

Customer:

yea

Customer:

no trouble codes

Kalamykid :

You will need to do this test when the engine will not start to see for sure what is going on.

Customer:

okay

Customer:

i will get back to u asap

Kalamykid :

thank you. If you have to wait till the morning when the engine is cold, I shoudl be online around 8 am eastern time.

Customer:

this morning it is not cranking and it still reads 5.05

Customer:

is there a way to check the spider on these trucks without pulling upper platium

Kalamykid :

I am afraid not. YOu can check the fuel pressure first, as this will some times save you time and labor.

Customer:

what do u suggest i check now

Kalamykid :

The fuel pressure would be the first thing i would check. We can check for injector pulse, but if there is no fuel pressure then the injectors will not be shooting fuel into the cylinder.

Customer:

60 on fuel pressure how do u check injector pulse on this type injection

Kalamykid :

you have to unplug the injector plug, and then with a test light connected to the positive battery post, see if the test light will flash when turning the engione over with the test light on any of he 8 pins other then the pink wired pins. The pink wires shoudl all have 12 volts on them.

Customer:

while checking the pulse it cranked by itself without starting fluid or anything and now it is cranking everytime

Kalamykid :

Did you unplug the injector plug when you did the injector pulse test?

Customer:

no

Customer:

but we have checked all connections on the plug and they seem okay

Kalamykid :

You will have to wait till the engine willnot stat, and unplug the injector plug and do the pulse test.

Customer:

i know i will get back to u asap

Kalamykid :

Thank you


 

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