Will not start when held to the floor, just cranks, will not start with MAP disconnected, just cranks..... test light hitting the relay...red wire lights, blue and white whire lights, blue and yelow wire no light but can here relay click, green and black wire no light...

Wish there was a way to bypass this and use a toggle switch to turn the juice on....I really appreciate all input and advise....I got this truck for 450, its a 1988 4x4 reg cab with 165k...and bought a 87 4cyl 5spd off the guy for 250.00

 

Im not sure if your truck has this, but a crank shaft position sensor would cause there to be no spark, same with Cam one. I would just check these. Maybe there is a loose wire on one, sometimes works sometimes not.

 

As far as I know there is no crank position sensor on the 88's.....

 

That is correct! An 88 does not have one. Unfortunetly the last thing to try is the pcm. And it is not unheard of for the ign. switch to go bad. And as far as the MAP sensor goes, it is on the firewall to the left of the coil . At least it is on mine. ANd just because it's getting voltage does not mean it's working.

 

Any one else have any more ideas? I am about ready to get a can of gas and a match.....truck ran great, no all it does is crank and crank and crank....killed a brand new week old battery...i have had it for 4 months and it ran great, now nothing

 

You should locate and check all the fusible links too. The links are quite commonly used on the ignition circuit. And also (per earlier instructions) remove the plugs from the pcm and check to kake sure none of the connections are loose.

 

Anyway around the ASR, by running fuel pump and ignition power off of 2 toggle switches? I am just wondering if this would work, in theory it should be possible, but there is always reality....I ordered a PCM through work today, but will take 5 days to get here, and if I can set this up with toggles to see if it works, may help eliminate the PCM as problem

 

Update...

Have fuel pump running off toggle switch....no problem unless forget to shut off and burn up pump.... After taking apart wiring at ASR...green/black = fuel pump......blue/white= IAC/ISC...best bet run it on toggle with fuel pump?

Blue/Yellow....not sure where it leads yet.....assume something that controls spark issue....Red=Power

Any leads so to speak on the blue/yellow? and since this sems to be working, best bet switch ignition over to push button

 

The ASD relay will have 4 wires going to it.
Blue - Switched power (from ignition switch)
Blue/Yellow - Switched ground from PCM
Red - Constant power
Green/Black - Power out (to fuel pump motor, injectors, heated oxygen sensor, ignition coil, and also an input to the PCM so it knows the ASD in "on")

With the boldened circuits not proving power (for blue) or ground (for blue/yellow) the ASD will not operate (send power out the green/black wire). Since you already said the fuel pump works when the truck has not beed modified (toggle switches, etc), we know the problem does not lie with the wires going to the ASD which means you can stop thinking there is a problem in the ASD control circuits. THERE IS NO NEED TO BYPASS THE ASD AS THAT IS NOT WHERE YOUR PROBLEM LIES!!!
Your problem may lie with the wiring to the ignition coil (from the ASD), but bypassing the ASD WILL NOT fix that!!
You need to get a multimeter and set it up to measure resistance and measure the ohms between the output of the ASD and and the positive input to the coil. Than go and wiggle some connectors and wiring harnesses and see if that changes anything. Than do the same thing from the PCM to ignition coil ground connection.\
On both circuits, you should get virtually no resistance. If you get an open reading or high resistance, the circuit must be repaired.
See the FAQ's post for wiring diagrams to assist you.

 

Update...

Dont know how I did it but I got rid of the relay, made sure fuel pump kicked on when hit to 12 volts, did some rewring, used a toggle, and boom truck started right up, and is runnng,I am off tomorrow, brought home my Fluke, some wire, fusible links, solderng iron, and plan on spending the dayunder the hod sorting through this mess of wires, that were not wrapped,loomed, or anything...hopefully, I will have more than a 10 minute drive tomorrow. I do appreciate all the advise, help, input etc...and will updatemore tomorrw