Cranks but no start...continued *SOLVED*

[mtimko57]

Hello All,

I got an all stock 98 Tahoe 5.7L. To start, a few months ago the thing just died on me during a short trip. It turns over but wouldn't start. I have since replaced multiple ignition components (alternator tested fine, distributor cap, ICM, etc...). I ran the complete troubleshooting procedure for the ignition system and all signals checked out perfect. The fuel pump was about 2 years old, less than 10k miles (just use it as my get dirty work horse). Since it has been dead and sitting, the fuel filter was replaced as well. It sat there most of winter, while I would go poke around at it here and there on nicer days. Still cranking but no signs of starting.

Finally I got ahold of a local shop to get it towed to because I gave up and it sitting there is starting to get in the way. I called AAA to come get it and the driver was chatting with me about the problem. He walked right over to the fuel tank, banged on it a few times, and it fired right up!!!! He said I ought to get the pump replaced. OK well I kept the Tahoe to do the pump replacement myself. I let the Tahoe run for about a half hour while I did yard work. I shut it off and it started right back up. A few hours later my wife and I were going to take it for a spin. Wouldn't start again! Tried the banging trick and nothing. Turns over and cranks but hear no signs of wanting to start. I order my new pump and just got it all back together today. Fired up after a few cranks but quickly died. It went back to the cranking with no signs of start. After about 5 minutes it started up and would only stay running with me giving it gas. This lasted for about a minute and it died again. Now it is back to the cranking with no signs of trying to start. I am stumped at this point.

I thought it was solved!!!! Also previous to the engine dying off a few months ago, I has ZERO signs of anything going bad, just up and stopped working out of no where. Fired right up every time and ran like a beauty.

 

[Doubeleive]

did you buy a oem fuel pump or something else?

 

[mtimko57]

oem. I can hear it also working when I turn the key to on.

 

[Jason in DLH]

I find ChrisFix videos helpful. Here’s a great video of his that may shed some light on the issue for you...

 

[wjburken]

I’m going to ask a very silly question, but you did put more gas into the fuel tank after putting the pump back in, right? If so, how much?

Did you change the fuel filter when you put the new pump in?

 

[mtimko57]

I removed about 15 gallons of fuel and there was still quite a bit in there (started off with 7/8 tank). When I installed the tank back in I dumped about 5 more gallons back in there. The fuel filter was replaced in December when I just started throwing parts at it.

 

[Fless]

Get a fuel pressure gauge on it and run the appropriate tests on it.

 

[exp500]

When you did the ignition tests, did you do a spark test at the distributor coil terminal? And did you use a Delco cap? Tools needed- scanner, spark tester, multimeter, test light, fuel pressure guage with long hose.Do you have these? Are any codes set? Any pops or backfires.
Try cycling the key to on/off 3 times before you crank it. Next try rotating coil wire 90 degrees while pushing into distributor. Did you replace the wiring connector at the fuel pump, most pumps come with them.
Lastly- are you trying to run it with 2 year old gas?

 

[TJ Baker]

I might be way off but does this vehicle have that 'spider' fuel injection? That system needs I think it was like 60 psi fuel pressure to operate. A year or two ago a friend had this issue, the new fuel pump, a Delphi would not develop the needed minimum pressure. I returned it to Napa and got a replacement, also a Delphi and tested that one in the tank before reinstalling the tank. That pump did the job. Just because a fuel pump is newish doesn't mean it is good to go.

 

[mtimko57]

When you did the ignition tests, did you do a spark test at the distributor coil terminal? And did you use a Delco cap? Tools needed- scanner, spark tester, multimeter, test light, fuel pressure guage with long hose.Do you have these? Are any codes set? Any pops or backfires.
Try cycling the key to on/off 3 times before you crank it. Next try rotating coil wire 90 degrees while pushing into distributor. Did you replace the wiring connector at the fuel pump, most pumps come with them.
Lastly- are you trying to run it with 2 year old gas?

Yes I got good spark. Not sure the brand of the cap, picked it up back in November. I need to get a fuel pressure gage and give that a test. No codes are coming up. No pops or backfires.

HAHA no not 2 year old gas, the gas probably isn't the greatest right now but it's from November

 

[exp500]

Fuel pressure test key on engine off- result. pressure after it leaks down- time to 45lbs. Pressure Idling, Pressure when on the road. Fuel trims long term/short term. Misfire counts per cylinder on a couple mile drive.
Re-read Post 8 and answer, after trying tests there.
Many/most aftermarket caps burn thru. Delco and United DCR820x are ok.

 

[YukonGTmaster]

I just did the fuel pressure check on my 97 Yukon before changing out the Spider to MPFI unit. At key on the PSI was 65. But quickly bled down. I suspected the Fuel pressure regulator. My new Spider from Motor Man came with new regulator installed.

 

[mtimko57]

UPDATE: So I ran the fuel pressure test today. Reading 60 at first and then bumps down to 55 and held there. Kept it on for about 20 minutes and list maybe like 3 psi. Still no start. I put in the spark plug tester and nothing!!! Something is going on between the distributer and the plugs I suppose.

I suspected it was the ignition system at first and replaced most of the components and troubleshooting seemed fine, even got spark. And also if there is no spark, why was the fuel pump not working before and after it got smacked a few times it started right up.

 

[YukonGTmaster]

UPDATE: So I ran the fuel pressure test today. Reading 60 at first and then bumps down to 55 and held there. Kept it on for about 20 minutes and list maybe like 3 psi. Still no start. I put in the spark plug tester and nothing!!! Something is going on between the distributer and the plugs I suppose.

I suspected it was the ignition system at first and replaced most of the components and troubleshooting seemed fine, even got spark. And also if there is no spark, why was the fuel pump not working before and after it got smacked a few times it started right up.

I have 415,000 Kms on my 97 Yukon. I am on my 3rd Fuel pump. I am ashamed to say that I sometimes let my fuel tank get dangerously low before refueling. The reason it was so dangerous, was because the last time I had to replace the pump, the electrical connector that was submerged in fuel with the pump, got so hot it Melted! I replaced the Pump with OEM AC Delco, and it’s been running for about 150,00 Kms. If I had to guess I would say 95% it’s fuel pump working intermittently.

 

[exp500]

One more time- Tell me what tools you have from list suggested so I can tell you how to diagnose this.
Do you have power at ignition coil plug at key on? Test light or multimeter on plug.
Fuel pump output low, I like to see 62-68. should run at 60. Swap fuel pump relay.
I'll get a couple reference diagrams/charts/instructions together forya on spark tests.
When you were driving it, Did you ever notice the tach bouncing around ?

 

[mtimko57]

One more time- Tell me what tools you have from list suggested so I can tell you how to diagnose this.
Do you have power at ignition coil plug at key on? Test light or multimeter on plug.
Fuel pump output low, I like to see 62-68. should run at 60. Swap fuel pump relay.
I'll get a couple reference diagrams/charts/instructions together forya on spark tests.
When you were driving it, Did you ever notice the tach bouncing around ?

I got all of the tools.
The Haynes manual is saying 60 is good for the fuel at start up, I will try to swap the relay.
I have power at the ignition coil. There was a full diagnostic instruction of the ignition system I followed and every signal was there up to the distributer (which is new since I broke down). I have seen spark by taking the plug out and touching frame. I put a spark test light on it last night and saw nothing. Not sure if it was polarity sensitive so I tried it both ways.
I went through the wire schematic for the ignition system testing not only the signals, but continuity as well.
No I did not notice the tach bouncing or anything like that. I did not notice anything unusual at all before this happened.

 

[exp500]

Last night I read your original post also. Throughout this dilemma you are giving short answers to detailed questions. Those questions are meant to eliminate a possibility or determine next step. You have the complete IGN troubleshooter.
Because of the parts cannon approach, you never determined your original failure, And yet you seem to want to argue about others long term experience.
If you are using your november test results as a BASIS for todays questions, we have a problem.
If you have a ICM pulse, and power at coil plug, Then coil is not grounded or coil is failed. Retest ICM, Retest coil plug. Add ground wire to firewall stud to engine. Should test to .1 ohm. Or you have bad grounds all the way to battery.
You have a new distributor- do you have a P-1351 code? Does your reader show cam offset? Any other codes? Have you inspected the distributor cap for burn thru? You left many unanswered questions. This is the last chance I'm giving.

 

[mtimko57]

Last night I read your original post also. Throughout this dilemma you are giving short answers to detailed questions. Those questions are meant to eliminate a possibility or determine next step. You have the complete IGN troubleshooter.
Because of the parts cannon approach, you never determined your original failure, And yet you seem to want to argue about others long term experience.
If you are using your november test results as a BASIS for todays questions, we have a problem.
If you have a ICM pulse, and power at coil plug, Then coil is not grounded or coil is failed. Retest ICM, Retest coil plug. Add ground wire to firewall stud to engine. Should test to .1 ohm. Or you have bad grounds all the way to battery.
You have a new distributor- do you have a P-1351 code? Does your reader show cam offset? Any other codes? Have you inspected the distributor cap for burn thru? You left many unanswered questions. This is the last chance I'm giving.

I never determined my original failure. It pretty much sat all winter. I did try the parts cannon approach and I tried the full IGN troubleshooter after. I tested everything with my multimeter and my test light. All of the ignition parts and signals test right where they should be up to the distributer. I have no positivity that the distributer is working fine other than I have seen a spark and it is brand new. This is where I got to in November. The Tahoe never started and I have not tried since then until last weekend. It sat in place for the wetness of winter. I gave up on trying and just wanted the thing towed. This is where I was as of last Friday, it hasn't been touched since I did the test results in November so I wouldn't think that any of those test results have changed or got altered since it just sat there.

Lets start with what I did have. I can try again when I got some free time again this weekend. I did have the ICM pulse and power at the coil (Coil is new as of November). I am unsure about spark from coil to distributor. Am I able to put the spark tester in there?

The dist. cap is new also as of November. I do not have a CEL but my code reader is giving me that code. I have one of the cheapo Bluetooth ones from eBay (using the torque app) and don't think it has cam offset (It might, I will dig into it later as well).

Definitely might have a ground issue as I tested that yesterday and was getting many different readings, usually around 0.4 ohms. I was thinking around a bit today and want to investigate that option of a ground issue some more. There is one ground I see by the distributer area to the frame. I sanded around a bit and got a good connection to the frame. I was unable to clean the other end, the space was too tight to get into. I see there supposed to be another ground on the other side but I can't find it.

Last night I did not get any light from the spark tester on 2 of the plugs (only tried 2, the 2 easiest to get to).

My mind got switched to something other than ignition when the tow driver smacked the fuel tank and it started right up and sat there running just great. That was the first time I had it started since November when I broke down. Would you have any explanation for this?

Sorry that I have been short and missing questions, I have 4 kids and a wife always needing me so I get in what I can. Already got distracted 3 times writing this. Thanks for taking the time to give me responses, it is appreciated. Didn't mean to sound like I was trying to argue.

 

[exp500]

Lets get you going in the right direction. Update your torque app to torque pro and add extended GM PIDS, set up cam offset degrees. key on read codes. clear codes. 1) add ground wire to firewall stud to engine, anywhere easy and out of the way, prefer 10 Ga but anything will work for now. 2) test ICM Plug 3) test coil plug. If those test ok, spark tester to coil terminal.If that works spark tester to dist coil terminal. If that works try to start. If a P-1351 shows on scanner move dist a little and retighten and remember direction. If you marked dist when removed and it lined up after exactly then you are close. Cam offset is "0"+/-"1" above 1000 rpm. Keep moving Dist till it starts, then adjust to final 0 degrees. Don't crank it with dist loose, it will move. 2handed loose is ok but tighten after final setting.Try that and report back.
Also order a new dist cap, you WILL need it.

 

[DonM3Z]

Same thing happened to me during a long trip. Yukon just died as I was driving. Would crank but not start. Classic symptoms of a fuel pump dying. Stranded in the middle of nowhere I grabbed that wheel wrench and banged that fuel tank. She started right up and managed to drive 50 miles to a shop.

Since was out of town got a Napa fuel pump which was like $250. Been a year and 7,000 miles and works like a champ.