Hello everyone

please, please, please help.
I got this truck from a friend who claimed that the truck was overheated at one point. truck was sitting for 2 years.
here's the long story of where I have been already. drained coolant, was red colored but not cloudy or gritty so ruled out rust being and issues. Got ratchet on the engine and broke engine loose from sitting (i did feel pressure on the heads while turning the engine over notice the exhaust was detached right after the manifold right before cats (so no back pressure issue). I replaced the Battery and checked engine light (it was on but went out while turning engine over then came back on, more about this in a second). checked the Fuel pump, non operational. Replaced pump, cleaned tank out, tested Fuel pressure sensor and fuel pump wires all good. Purchased ELM327 device and computer program. System said no codes and the light was not on. this made me think that the light is still in test mode and would go out if the truck would just start. So then on to the engine. replaced all plugs and gapped to .052 as called for. have inline tester and i have spark but it may be weak. wasn't getting a blue spark. but since they were new plugs I wanted to try something else. I tested the resistance on all wires checked out ok. Tested the coil pack and it was giving a high low end resistance so I replaced just in case. New Coil was well within specs. Tested the Idle Air Control with MultiMeter worked good. checked throttle position sensor with multimeter at open and closed, tested good. Computer measures the TPS at 18.8% closed and 97% full open. Tested and replace the Crankshaft Position sensor. Check fuel pressure 30% initial and 60% when cranking. pulled intake manifold and clean it out. while off I pulled all 6 fuel injectors, tested and cleaned. cleaned EGR tube and check sensor. blew the bendix gear while trying to start the thing and had to replace that too. OH AND I INSTALL THE F'ING KITCHEN SINK!!

So here is what happens. if I try the truck after its been sitting. first try with no pedal at all. it will sputter and backfire out the disconnected exhaust. then I get nothing unless I floor the pedal. I get and occasional sputter and alot of trying to start for 5-10 seconds and occasional back fire

 

if you have fuel and spark ............ I still think the crankshaft position sensor might be bad

 

"no codes" is a problem............ not sure why that don't work.

 

The backfiring would suggest you have fuel and spark. Pressing the throttle to the floor will shut off the fuel injectors (Wide Open Throttle => WOT) and since the engine acts a bit more like it wants to start then might suggest a flooding condition. Since you have spark, the crankshaft position sensor is at least triggering.

You stated that you cleaned the fuel tank out when you replaced the fuel pump. Did you put that old gasoline back in, or did you put in fresh fuel? If you used the old fuel, it may just be so contaminated that it doesn't fire like it should. Drain the fuel and start with fresh to see if that changes things. You could also pull the fuse for the fuel pump or unplug the inertia switch, crank the engine a few times, then spray some throttle body cleaner or carb and choke cleaner past the throttle plate, crank the starter over and see if the engine will start and run for a second or two when provided with the cleaner versus fuel. Once you establish that, you can start to rule out things like spark and timing and focus your efforts.

-Rod

 

Thanks guys for the assistance. nice to have some help cause 3 months working on this is getting stressful.
when I was first working on it I tried some starting fluid behind the throttle plate and no change but i will try purging the lines first by unplugging the relay.

I have a timing advanced signal and reading in the ELM327 data so that would lead me to believe that the CPS is ok, right? also considering its brand new. i could back pin it with a multimeter. any idea on specs for that?

 

If you back probe the Crankshaft Position (CKP) sensor, and assuming you do not have access to a handheld oscilloscope, use ACV setting and check for voltage while someone else engages the starter. If you get an AC reading while the starter motor is spinning the engine, the CKP sensor is likely okay. Watching the square wave output with an oscilloscope is the more fool-proof way to test the sensor and the gap though.

-Rod

 

If you back probe the Crankshaft Position (CKP) sensor, and assuming you do not have access to a handheld oscilloscope, use ACV setting and check for voltage while someone else engages the starter. If you get an AC reading while the starter motor is spinning the engine, the CKP sensor is likely okay. Watching the square wave output with an oscilloscope is the more fool-proof way to test the sensor and signal integrity though.

-Rod

 

Ok so I purged the fuel lines by pulling the fuel relay and cranking it over a few times. the sprayed the starting fuel behind the throttle plate. At First nothing then after 2 or 3 tries at cranking it over I got a little bit of wanting to start.
This is a new one on me. Every time I have ever used starting fluid and its been a fair amount of times on engines from weed wackers to generators to cars, I have never had a long delay like that. starting fluid, in my experience has also been instantaneous effect.

 

I'm wondering if this could be an air intake issues. I pulled the manifold and cleaned it out the other day so I know it is not in the plastic manifold.
I just think that I am only getting something at WOT meaning full air intake and now the delay in the starting fluid getting into the chamber. But what am I missing

 

Try unplugging the Mass Air Flow (MAF) sensor, then try the starting fluid spray again. If you had the intake air tube completely removed and sprayed the starting fluid in to the throttle plate, the open MAF may have caused the delay in trying to start. Your small engines that you've used starting fluid on in the past didn't incorporate MAF sensors. When I use throttle body cleaner for this I will typically locate a small vacuum port or pull the PCV tube off the intake so I can seal off most of the hole or spray the cleaner in the throttle plate, the position the intake air tube back on the throttle body to try to start the engine.

-Rod

 

unplugged the MAF and this time got nothing at all!
10 cranks and nothing

Yeah I know the small engines are much different, after I typed that I realized how stupid it sounded. but I still never had it happen on a car either.

 

Have you tried spraying in the intake, then reconnecting the intake air tubing, with the MAF plugged in?

-Rod

 

same results, after about 5-6 cranks there is a thought of starting.

 

That's interesting.... I'm not sure how to explain that. You might want to pull a couple of spark plugs and see if they appear to be saturated in fuel or fouled, etc.

-Rod

 

I will try that, although I just put new plugs in.

Could it be air intake? here's my thoughts, delay in getting the starting fluid back to the pistons, don't get anything unless WOT which also means full air intake? if there is an air intake issue then that could mean restricted of decreased air flow, right. I only took off the upper manifold. I am thinking of tracing the air all the way back to the pistons and checking for issues. Any thoughts?
I'm glad you are stumped as well, cause I was felling like a shade tree idiot.