259D no start w/key will start with power relay

[gatorchevy88]

I have a 259D (FTL14492) (ESN 8HN5725), with a rather confusing issue.

cold: with key no start. key on engine off if you press in the relay it will start no issue

cold - warm: will start same with relay, and will kind of start eventually after a few cranks with key and flutter pedal

hot: starts immediately with key and relay

have replaced fuel rail, transfer pump, filters, engine wiring harness, machine ECM, tried to replaced engine pcm (site to reprogram c3.3 currently down).

conducted a cylinder cut off test and the delivered fuel injection was 16.7 - 18.3 mm3 across the 4 injectors. I believe spec is 25mm3. not 100% positive. however fuel rail PSI was in spec at low and high idle

slightly weird issue because every path you get on to see why it wont start with key all theory gets shut down because it will start with power relay when pressed

thank you in advance for help

 

[Mark250]

Hi trying to understand your problem
are you saying that the machine cranks with the key when cold, but wont start or are you saying the machine wont crank with the key when cold, but will crank and start if you jump the start relay ?
What was the reasoning behind changing the machine ECM, the fuel rail, the engine harness,and also the fuel transfer pump?
will ET connect to the engine ECM?
Are there any codes logged or active?
Are any fault lights on?
have you checked the interlock i.e. seat switch and armrest switch is working correctly
sounds like you are also changing the engine ECM? why?
where are you getting the engine ECM software from ? your post makes it sound like it is non Cat
Mark

 

[gatorchevy88]

hey mark sorry for confusion.

cold key will crank no start. pressing relay in will start immediately.
however I just got to the shop turn key on let site on on position for full 30 seconds of prime, key off, then back on for full 30 seconds then tried to start. had a long extended crank (roughly 10-15 second) sluggish and rough but started.

ecm, rail, and harness changed by another tech before it got in my hands. transfer pump changed due to a result I ended up at from test in cat ligature.

ET will connect to both ECM

no active or logged codes, no fault lights.

have not checked interlock, seat or armrest.

engine ECM was getting changed as a try and see if that's the issue. but did due to program website down didn't get changed. software is coming directly from SIS for the 3.3/3.8 engine.

 

[Mark250]

Ok, sounds like you are playing with the power circuit relays items 22 and 23



turning the key on will energise power relay 1. with a voltmeter check for 12 volts at the purple wire #112.(engine cranking) this will supply power to pin numbers 13 and 33 of the engine ECM, this will put a negative return on pin numbers 3 and 23 of the engine ECM which are the return wires of the ECM power relay. this will turn the ECM relay on supplying voltage to the engine ECM pins 1,18,21,38,58,and 78 Check for 12 volts at the orange wire #150 at the ECM power relay (engine cranking)
if there is low voltage I would check the fuses and connections in the relay modules
if no voltage at the ECM relay #150 wire I would make sure the interlock are correct (ET is best for this)
Also check the fuse and connectors 10a in the number 1 fuse block as it is between the power relay no1 and ECM pin numbers 13 and 33 labelled elek engine/lrc throttle

Mark

 

[gatorchevy88]

yesterday we the area in SIS for the 3.3 ecm flash came up. so we installed the engine ecm and flashed. it slightly helped. but still bouncing between original fault and very long extended crank before it catches to start

just now tested wire 112 received 12v key on and 10-11v when cranking, wire 150 received 12v key on and 10-11v cranking.

all fuses and connectors are good.

also the original relay I was talking about pressing in and it starts is in the engine bay mounted to left hand wall next to transfer pump

josh

 

[Vetech63]

Ive had issues with the female spades of fuse and relay locations being pushed out of the back of the holder. Worth a check anyways.

 

[Mark250]

sounds weird as you say. the relay on the inside frame is the start relay. when you ran your voltage checks ,did you use the key start position or the relay to crank the engine ?
the other relay in that area is the preheat relay. is it possible you are activating the preheat relay and the machine is starting with the added preheat

 

[Mark250]