Grand Cherokee won't start

[MSS]

My friend has a '93 grand cherokee that won't start. It is a 4.0 with an automatic. It is getting spark at the coil and at the plugs. Also it has ~40 psi of fuel pressure at the rail and it is pumping gas. Getting a '41' code.

Any thoughts?

 

[Kiel]

crank sensor?

 

[Fuller]

if it was the crank sensor it wouldnt get any spark

 

[74highboy]

try starting fluid ive had a simular problem it had fuel presure but it didnt have any volume try starter fluid

 

[Fuller]

try starting fluid ive had a simular problem it had fuel presure but it didnt have any volume try starter fluid

yeah i have had the problem as well

 

[MSS]

Tried starting fluid - no luck. Opened the line in the fuel rail (with a fuel pressure gauge) appeared to put out a lot of gas.

Tank was down to ~1/8 when this happened -> put a few gallons back in and still nothing. Had been running fine earlier in the day.

Other notes - getting voltage pulses at the fuel injectors.

Any other thoughts?

 

[78mitsu]

cleaned/replaced spark plugs? check spark with a timing light or by touching it to your toung while cranking.

 

[Caleb]

same thing happened to my Dad's truck (95 S-10) see this thread for more info. It (supposedly) ended up being the fuel pump...I have a hard time believing it because I could watch the fuel from the injectors soak the throttle body and it wouldn't start on starter fluid but I had spark every where like you. Soemthing to atleast look into a little more closely. Also, I'd do soem digging on that Code, if it's as simple as finding out what a code 41 is then it should be easy.

 

[Caleb]

a quick google search came up with a fault in the charging system or no field current for a 41 code.

 

[Fuller]

have you tried changing the fuel filter?

 

[MSS]

- Timing looks to be on
- crank position sensor checks out ok


What's left? Computer?
Any other thoughts would be much appreciated - we are about to throw in the towel.

 

[wr250]

a quick google search came up with a fault in the charging system or no field current for a 41 code.

ac voltage from a faulty alternator will play havok with the computer. disconnect the alternator ( or belt), see if it will start.

in addtition, check cranking fuel pressure, should drop a bit (5 lbs maybe). if it drops excessively check fuel filter and pump. if it doesnt drop at all, fuel injectors have a problem; it should still fire on starting fluid (2-3 3 sec squirts).

injectors will pulse. they work like so:
there is key on 12 volts to each injector. the computer provides a ground at the right time to "fire" the injector. depending on how long the injector is grounded, is how long the injector fires.

i would say the low tank is a coincidence. if it wont run on starting fluid you have an ignition, valve timing (unlikely), exhaust (clogged/broken cat) or compression problem. the ac voltage mentioned above will effect ignition via the computer.

 

[MSS]

Update - was worried about timing chain so he pulled the cover. Crank and cam still lined up and chain looks good. I'm thinking the code 41 was induced from letting the battery run dead from cranking.