93 Blazer 4.3 "W" won't start

[91 drggn dime]

I am having the SAME problem out of my 93 blazer with the CPI 4.3... it ran great for 3 weeks (most its ran in 2 months at 1 time), came to a stop sign, stopped, hit the gas, chugged once like it was out of gas, died.. after putting 9 gallons in it, still wont start. everyone i talked to said it sounds like it skipped timing.. pulled it down, hand turned motor till dots lined up on the timing chain, piston was TDC, but dizzy was 180 out.. so we turned it around, still wouldnt start.. timing chain was stretched some, 178,500 on stock one.. s oi changed it out.. everything still lined up, still wont fire. It is getting fuel and fire. fuel pump is new, pickup coil is new, coil is new, igniton module is new, injector is new.. it spins faster then heck, but wont start. when it primes and i push the shredder valve, fuel hits the hood..

is there any kind of relays or anything? only SES code is 22.. TPS voltage low.. i put a new TPS in it but still get that code. how can i up the voltage? what runs that?

[Sparky2263]

, hand turned motor till dots lined up on the timing chain, piston was TDC, but dizzy was 180 out.. so we turned it around

When the dots are lined up nearest each other you're at TDC #4 cyl. When the cam gear dot is at it's peak (180 deg turn on cam gear, 360 turn on crank gear) is TDC #1. So the first thing would be to obtain TDC #1 by removing the #1 spark plug, bumping over 'til you feel compression and lining up from there.

What kind of plugs are you using and what does the tip look like?

As far as the code 22, that won't cause a no start. I'm curious of the voltage readings on the 3 wires though.

(posts moved to their own thread)

[91 drggn dime]

the plugs look a little wore.. they are AC delco.. TR something, i'd have to take one out to see..

i just got doe bolting the opil pan back up, we were gonna do a 'see if it starts' but then i read about how cranky the cpi's are, so i figured if i put the pan back on we might have better luck..

thanks for the move..

so did i flip my dizzy for no reason and i need to flip it back around? we did feel for number 1 being up and my stepdad said it was.. it could have been slightly up and 4 could have been all the way up.

[91 drggn dime]

update.

flipped the distributor 180 back to where it was when pulled.

got it to start.. but now it does what it did before the timing chain got pulled.. revs up and then sucks air, then revs then dies..

only code is my TCC lockup which i knew about.. i'm sure TPS code will come back.. ifthe voltage is low and a new one is put in like there was and it still says low.. what is the problem?

will this surge at idle be EGR valve?

[91 drggn dime]

everyone i have called seems to tell me that if those 2 have been replaced, the tps and iac.. then its most likely the computer.

[91 drggn dime]

When the dots are lined up nearest each other you're at TDC #4 cyl. When the cam gear dot is at it's peak (180 deg turn on cam gear, 360 turn on crank gear) is TDC #1. So the first thing would be to obtain TDC #1 by removing the #1 spark plug, bumping over 'til you feel compression and lining up from there.

What kind of plugs are you using and what does the tip look like?

As far as the code 22, that won't cause a no start. I'm curious of the voltage readings on the 3 wires though.

(posts moved to their own thread)

I tested the volts to the TPS.

if i stick the ground prong into the bottom wire, the top right one is the only one that reads, it reads .5 volts.. if i stick the ground prong into the top right wire and probe the top left, it reads 2 volts.

if i ground the ground prong and go through the IAC harness, i get 2 volts on the first one, nothing on the second, 2 volts on the 3rd one, nothing on the 4th one.

[Sparky2263]

Sounds like the ignition timing is way off. Now that it'll start, try turning the distributor back and forth and see if you can get it to idle.

Also, the voltage measurements need to be made with the negative lead attached to the ground post at the battery. Probe the 3 tps wires with the positive lead. The 3 measurements should be;

Black wire less than .2
Grey wire 4.5-5.0
Dk. Blue ~.5

[91 drggn dime]

the timing is off.. it runs like crap turning it either way.. would this be the reason of a tooth or 2 off?

i'm so fed up with it.. when its fixed, its forsale.

lemme go probe those wires really quick for you.

[91 drggn dime]

ok.. black prong attached to neg on the battery.. the dr bl is 0.. black is 0.. grey is 2 volts with key on.

anything can cause this?

[91 drggn dime]

I have a bravada computer laying around for testing purposes.. even with it plugged in and my stocker unplugged.. same voltage comes from the wires.

i cant even get it to give me the voltages i posted earlier doing it the method i did it then. no clue why.

[Sparky2263]

The grey wire feeds the MAP, TPS and EGR sensors with a 5 VDC reference signal. Disconnect all 3 and see if the grey wire is capable of reading 5 VDC then. If it reads 5 vdc with all 3 disconnected, plug them back in one at a time to see which one pulls the 5 vdc reading down to 2 vdc.

I'm wondering if your egr valve isn't stuck open making it run bad.

[91 drggn dime]

I will have to do that tomorrow when i get home from work. Thank you i'll report back then. This CPI is all new stuff to me.

[91 drggn dime]

unplugged both MAP and EGR and i still only get a 2 volt rating from the grey wire. nothing from either other wire.

[Sparky2263]

With all 3 unplugged you only have 2 volts on the grey wire? If so, need to isolate the grey wire at the computer to determine if the wire is shorted somewhere or the computer is bad.

Ck. the positive connections near the battery also. Make sure no corrosion has taken over.

[91 drggn dime]

i'll do that.. i've put a computer from a bravada in it.. 93, cpi also.. same voltage.. could my prom be theonly bad part?

also with a dead dr bl and black wire.. would that be the grey shorted out?

know where i can get a pinout of the ecu?

[Sparky2263]

With them all disconnected the black and blue wires won't read voltage. The black is ground and the blue is voltage return (sensor voltage).

Here's your wiring.

[91 drggn dime]

thank you for those.. that will help a TON.

the volt meter ihave is a craftsman.. it has 50 something, 100 something and 200 something settings.. i have it on 50 and its reading 2 volts.. i dont know if that matters any. i'm not an expert on using a voltmeter.

[Sparky2263]

0-50 is not gonna get you close on 0-5 volt readings. Are you using the DC scale? Most DVOM's read on scales single and double digits, i.e., 0-2, 0-20, 0-60. Especially DC volts. DC readings rarely top 100, especially automotive.

[91 drggn dime]

hahha.. i feel completely stupid eevn posting this... buuuuut, i had it on AC 50. I will try it tomorrow on DC.. my meter has DC 10, 50, 250, 500.. i should test it on 10 right? sad, i can build you a frame for your truck and lay it out, but i cant operate a voltmeter.. i'm retarded.

[Sparky2263]

Yup, yup. 0-10 would be the scale.

Don't feel bad. Buddy of mine is a monster painter but trying to teach him how to set float levels on his Holley is like pulling teeth.........

;)

[91 drggn dime]

ok checked it the RIGHT way.... grey wire.. 5 volts.. other 2, dead even with egr and map unplugged

[Sparky2263]

Excellent. Now plug 'em back up and see what the return voltages are.

[91 drggn dime]

I did. i checked it both way.. return wires are dead with em plugged in or unplugged.. i even unplugged em 1 by 1..

i will double check again when its light out.

[Sparky2263]

MAP return voltage should be around 4VDC key on, engine off. TPS should be around 0.5VDC. Same with EGR postion.

[91 drggn dime]

ok double checked.

dr blue wire is .5 volts
grey is 5 volts
black wire is 0... with key on, engine off, with it on AC 0-10

making a little bit of lee-way i presume.

[91 drggn dime]

...bumpity...

[Sparky2263]

Plug them all back in and re-check the voltages. Use the wiring diagram I gave you to reference which wires you're talking about.

[91 drggn dime]

all 3 were plugged in when i got those last readings.. and then done it unplugging them one by one, same voltages.

i'll go through the diagrams u gave me when the rain lets up and drys out.