1999 stalled after plugs, wires and fuel filter, help please

[dukcaln]

Did you actually measure the fuel pressure or just depress the Schrader valve stem and see fuel spray out? Did you happen to add fuel to the tank just before driving away from your house?

When I was a kid there was a prank to plug the tailpipe with something. The engine would start and run for a short period and then die from the exhaust back pressure and not restart. However, with ODBII I think if your cat or muffler were blocked a DTC would be set. You never answered koda2000's question about any DTCs being set after the engine died.

How did the spark plugs look when you repeated the compression check? What gap did you set the plugs to?

What did you mean by "cleaned the cam sensor" in your first post?

62 was fuel pressure, no fuel added, not one code before or after engine died. plugs look like it was trying but smelled like fuel

 

[2000StreetRod]

cam sensor

The camshaft position sensor on the SHC V6 is located on the driver side just aft of the oil filler tube.

It allows the PCM to determine whether cylinder 1 is on the compression stroke or the exhaust stroke.
The camshaft position sensor (synchronizer) on the OHV V6 is located at the top rear of the engine near the firewall. Are you sure your engine is the SOHC V6? The 8th digit in the VIN should be an "E"?

 

[dukcaln]

2000, yes it has the E on the 8th digit. We did not check or replace the camshaft sensor. Just the crank sensor. Will the cam shaft sensor cause a stall and no start? I know the crank sensor can but I was told the cam shaft sensor will default and still run. Is this accurate or was I miss informed? I guess I can suggest to my buddy at his shop to replace the cam shaft sensor. Anything else?

When he attempted to start it this morning it initially cranked and acted like it wanted to start. So he tried again and all it does is crank. No stumble like yesterday. Hmmmm!!!

 

[drdoom]

The CMP sensor is simple to test. I believe you want to check the harness for signal 1.5V then check the sensor while cranking with a meter, set on the AC setting, checking for voltage pulses.

 

[dukcaln]

Ok thank you. Will do that test on the CPs , Update. Replaced coil. No change. So if we hold the throttle to the floor it will stumble during cranking like it wants to start. If we don't hold throttle it will just crank. We double checked spark, even replaced the coil. Fuel pressure check again it good, 64 ish psi. Fuel pump comes on. Comp test again good. Checked maf good. New crank sensor, double check code on shops diagnostic tool. No codes. Double checked the inertia fuel switch, good. Looked through oil cap fillet while cranking. No visible wear metal tension issues on timing parts.

Totally amazed and stumped

 

[dukcaln]

To clarify. What is the fuel pressure statue at the valve stem? I get between 65 and 70 on the gauge?

 

[2000StreetRod]

fuel pressure damper

Your 1999 has a returnless fuel system with a fuel pressure damper on the fuel rail.

It has a diaphragm in it that can rupture allowing fuel to get sucked into the intake manifold. I suggest you disconnect the vacuum hose from the fuel pressure damper. If fuel is present in the hose then replace the damper.

The only reason I asked about the camshaft position sensor is because in your first post you stated that you cleaned it. I thought perhaps it wasn't reconnected properly.

 

[dukcaln]

2000, thanks again, could this rupture with the newly found fuel pressure and flow in the system after the fuel filter was changed? because the old fuel filter was dang new completely clogged.

we did try to disconnect the fuel pump and just turn it over with starter fluid, it tried to run but stumbled like crazy, more than every. never got to a full run, so that is why we are maybe suspecting the fuel pressure regulator. but the psi at the valve is 65-70. the spark is strong, new coil, but the plugs still smell like fuel... going to recheck the compression...

we will check the damper now.

 

[dukcaln]

so each side seems to have good compression, the oil smells like fuel and so does every plug, wet. 65-70 psi at rail, but bleeds down slightly while sitting, but no much. so i am thinking, bad pump too much pressure, regulator), bad damper causing fuel in manifold leaking to cyl to oil, jumped timing, open injectors (all), or internal mess... am I on the right path?

 

[rb142]

It sounds like it is getting flooded with way too much fuel. What are the fuel trims? You might pull the battery cable for a few minutes to reset everything and see if there is any difference. Is there any restriction in the exhaust? It almost sounds like the spark timing is way off (but it did run for that short period).

What was the result of checking the fuel rail damper?

 

[dukcaln]

It sounds like it is getting flooded with way too much fuel. What are the fuel trims? You might pull the battery cable for a few minutes to reset everything and see if there is any difference. Is there any restriction in the exhaust? It almost sounds like the spark timing is way off (but it did run for that short period).

What was the result of checking the fuel rail damper?

fuel rail damper was dry. My buddy seems to think its the fuel pump/regulator. as in his words after consulting another mechanic the fuel psi is there but the fuel volume is not. He said by testing the fuel pressure again that when he presses the valve the fuel will not squirt out, very little actually comes out but the pressure is there. He said with his psi checker that the tube shows very little fuel in it when testing but the pressure is accurate. Any because it has been cranks so much, and prior to him getting it there has been too much fuel that has flooded the system. Now the oil smells like fuel and he suspects the intake is full of starter fluid now and yesterday a friend had the idea to put fuel in a cylinder to see if it will start, so we are just too flooded.

 

[koda2000]

the FPR is in the tank just above the fuel pump. it is part of the fuel pump assembly. another thing that can happen is that the short piece of hose between the pump and the regulator can become loose or crack. this limits the amount of pressure that the pump can deliver. if i had to drop the tank to check/replace any of those parts, i'd install a new pump while i was at it (if not the whole assembly).

in regard to testing the fuel pressure with a test gauge, some gauges don't fully depress the schrader valve on the fuel rail fitting. remove the valve to make sure you're reading full pressure.

 

[dukcaln]

I just can't see it being the pump or regulator but they seem to think so and are replacing it today. We will see if that is it or if that eliminates another source.

 

[dukcaln]

well, nope the pump wasn't it, its getting plenty of volume and pressure now, but it will not start, just crank. could the cylinders be flooded with fuel? should i pull the plugs and turn the car over to flush the cylinders?

at this point I am thinking timing, chain jump something.... any more suggestions please would be great

 

[koda2000]

well, nope the pump wasn't it, its getting plenty of volume and pressure now, but it will not start, just crank. could the cylinders be flooded with fuel? should i pull the plugs and turn the car over to flush the cylinders?

at this point I am thinking timing, chain jump something.... any more suggestions please would be great

assuming you've got air, fuel and spark... my next super wild ass guess is maybe a bad CPS? if the engine doesn't know what position the cam is in, it might be firing the plugs at the wrong time. sorta like a timing chain jump. i'm not thinking timing chain because it started at the dealership. a bad sensor could conceivably work intermittently.

 

[2000StreetRod]

not timing chain slip

If you have good compression in both banks (180 psi or so) the timing chains have not slipped.

The PCM uses the crankshaft position sensor for ignition timing and the camshaft position sensor to determine if cylinder 1 is on the compression stroke or the exhaust stroke. With the waste spark system cylinder 1 is paired with cylinder 5 (both fire at same time) and the firing order is 1-4-2-5-3-6. So for spark it doesn't matter if the cylinder is on the exhaust stroke or the compression stroke. However, for the injection pulse it does matter. Unlike the 5.0L V8, the SOHC V6 will usually not start with a 360 degree "stale" injection pulse. My Sport was abandoned on the interstate by a previous owner because of a faulty camshaft position sensor. In your first post you stated that you cleaned it. When I asked about that you said you didn't check it or change it. drdoom posted how to test it and you said you would but haven't posted the results. I'm not optimistic that it is the source of your problem but it is certainly something that should be checked.

 

[dukcaln]

If you have good compression in both banks (180 psi or so) the timing chains have not slipped.

The PCM uses the crankshaft position sensor for ignition timing and the camshaft position sensor to determine if cylinder 1 is on the compression stroke or the exhaust stroke. With the waste spark system cylinder 1 is paired with cylinder 5 (both fire at same time) and the firing order is 1-4-2-5-3-6. So for spark it doesn't matter if the cylinder is on the exhaust stroke or the compression stroke. However, for the injection pulse it does matter. Unlike the 5.0L V8, the SOHC V6 will usually not start with a 360 degree "stale" injection pulse. My Sport was abandoned on the interstate by a previous owner because of a faulty camshaft position sensor. In your first post you stated that you cleaned it. When I asked about that you said you didn't check it or change it. drdoom posted how to test it and you said you would but haven't posted the results. I'm not optimistic that it is the source of your problem but it is certainly something that should be checked.

Let me start out by saying thank you very much for your assistance. I know I said we cleaned the cam sensor in the first post, I actually meant to say the crank sensor on the front of the motor. but we did eventually buy a new crank sensor and install it. We have not checked or tested the cam sensor as drdroom suggested unless my buddy did it when I left, and didnt tell me, it was on our list. Maybe he forgot with the fuel pump change. I will go to his shop first thing in the morning and have the cam sensor tested. I am almost 100% positive the compression check in all cylinders was good, I will triple confirm tomorrow. Next step will be testing the cam sensor? could the cam sensor cause the car to just die while running, meaning go bad during operation? How difficult is the cam sensor to replace, time and difficulty level?

Again, i ca not thank you all enough..... its my nephews daily driver and its killing me I cant get this figured out for him... and he is driving my truck, Lol

 

[2000StreetRod]

replacing the camshaft sensor

It is easier to replace the camshaft sensor than to replace the crankshaft sensor. It is mounted on the valve cover behind the oil fill tube. You just disconnect the electrical connector and the two mounting screws and lift out the sensor.

 

[dukcaln]

well an update, will be replacing the cam sensor tomorrow. Car hs been siting for a few days because my mechanic friend was on vacation. Back at it tomorrow and we will see what is going on

recap, ran great after tune up, then stalled a few blocks. so stalled after plugs, wires and new filter.

cranks, plenty of spark and fuel, but wont start. New crank sensor, new coil, new fuel pump, checked the inertia valve, good, compression good all cylinders. Maf good. friend said he tested the cam sensor, but I said replace it tomorrow then try. So at this point everything says it should run..... please anymore advice would be so great

 

[2000StreetRod]

MAF good?

How did you determine the MAF sensor was good? Merely disconnecting it is not an adequate test. It is difficult to test if the engine doesn't run. Have you cleaned the sensor element with MAF sensor cleaner aerosol?

Did you happen to add fuel after the tune up? Was the fuel filler cap locked when you parked the vehicle after the tune up to prevent someone from contaminating your fuel? Did you drain the fuel tank to replace the fuel pump? Are you still trying to start the engine using the original fuel?

What spark plugs did you install? What did you gap them to?

Make sure nobody plugged your exhaust tailpipe as a prank.

Check the intake system (inlet cone/silencer, air filter, main tube) for blocks.