MAF Testing

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Dec 20, 2006 | 01:14 PM

#16

Terrence

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I just finished probing the injectors. I only thing I could verify is that there is 12v present. As I cranked it, I could not see any interuption or deviation of the 12v. But it still doesn't start without a blast of ether.
Thanks,
Terry

Dec 20, 2006 | 05:51 PM

#17

pawpaw

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From: SW Va

Terry, were you probing the ground side of the injector, the side who's lead runs to the ECM to be grounded?????

If you were probing the input side, you won't likely see any drop in voltage, as the injector fires.

If you don't have a wiring schematic, the output, or ground side of the injector should have slghtly lower voltage than the input side, due to the injectors coil resistance. So you might be able to determine which lead is which, that way.

Also your meter might not have a fast enough response time, to detect the pulse, so it might require a o-scope or a noid light, to see the pulse.

Dec 20, 2006 | 09:55 PM

#18

wtroger

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NO NO NO you are misunderstanding what Iam trying to say. Connect one terminal to chassis ground the other side to the ground side of the connector diconnected from an injector you should see an open condition and when the pulse is made it will show a dip in resistance depending on how fast your meter is.

Dec 20, 2006 | 09:59 PM

#19

Terrence

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I hooked up the meter and back probed the the fuel injector connectors. I found 12v present. I then cranked the engine over and watched the meter at the same time and did not see any fluctuation or deviation at all. So either, like you say it's not getting a pulse or the meter is not capable of catching it. I also looked for loose or corroded grounds and found nothing.

Terry

Dec 20, 2006 | 10:06 PM

#20

Terrence

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OK...I will disconnect a connector on an injector, switch the meter to Ohms, hook up to chassis ground and probe the connector. OK...I got it. I'll try that in the a.m. I let you know what happens.
Thanks for your support,
Terry

Dec 20, 2006 | 11:10 PM

#21

pawpaw

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From: SW Va

Terry, test & note the connector for the hot lead, the one with 12 volts DC on it, with your meter set on te 20 VDC range.

Then check the other lead without any votage on it, by setting the multimeter to the X1 ohm scale, as it's response should be a little faster, but I still don't know if it'll be fast enough to see the pulse, as it's pretty fast/short pulse width, for a meter to record.

Yup Roger I think we all misunderstood what you were suggesting, but maybe his meter will be fast engough to catch the pulse. Good idea btw.

If not, there is always the noid light & they can be purchased, or loaned at most auto parts stores.

This is getting to read like a soap opera, the saga continues, so tune in tomorrow, to see if the meter gets off, to the titillating tickle of a injector pulse!!!!! lol

Let us know how it goes Terry.

Dec 21, 2006 | 08:36 PM

#22

Terrence

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Today I checked for the gound pulse as suggested. I got the pulse when attempting to start the truck. It was very noticable. Now any other thoughts??
Thanks,
Terry

Dec 21, 2006 | 10:11 PM

#23

wtroger

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The manual under no start but normal cranks asks wether the engine will start at part throttle position. If it does then it says to check the IAC. I would give that a try and see what the results are hold the throttle open a little maybe a 1/4. See if it will fire off. I will do a little more research in the books and see if anything matches your symptoms.