[tigger_tat_55]

hi there,

got some problems with my toy.

it is backfiring thur the intake when cold, missing at all rpms and wont hold an idle.

what I have done: new pugs, cap, rotor, wires, checked for vacum leaks, set timing to specs.

am going to do: check/adjust valves, do compression check.

anybody got and idea what else i might look at??

also, the cpu is not showing any codes.

is it possible that a clogged Cat would cause this??

thanks

 

[tigger_tat_55]

timing was off a bit at first. have checked it several times since and it shows ok, when i check the valves i will check the chain. dont belive the wires are crossed but will check.

prior to the tune up it had started to run bad, after the tune up, just got worse..

 

[tigger_tat_55]

miles on the motor..... dont really know, it is bout 9 years old, was new when I got the truck,

cable to the speedo broke, I never fixed it. guessing bout 75k or so.

did this am, ajusted the valves, one of the intakes was a bit tight.
checked all ignition peices, used the factory book and went thur the coil/ignitor/ distributor, all checks ok within specs.

went to recheck timing after doing the above found that the cpu is now showing the airflow meter as a problem. have checked the resistance per the book. it shows ok. have run out of time this evening to do the other test on the meter.

other than the cpu code, this thing feels like a vacum leak, but I cant find it to save my life, maybe the airflow meter is giving bad info to the cpu and messing up the works...

plan to change out the fuel filter in the next day or so....who ever put the thing up under the intake should be hung...... only way to get to it is to remove the tire and go at it that way, most of the time i have to get one of my kids to reach in to help....


thanks to all that have added their imput, it has helped.:smile2:

 

[tigger_tat_55]

also,

plugs are ngk, new, gap is set to the specs went back thur made sure all the wires to the plugs were in the right order.

 

[tigger_tat_55]

its 1 3 4 2,

the wires are good.

have not done the compression yet will do it tonight or tomorrow. last year had a head gasket leak, took the head off replaced the cam, had the head checked/ put new injectors, cleaned all parts replaced all rubber lines and used new gaskets. while i was in the motor then, it appears that it is on its last rebuild, pistons were 3 over, i think. if the compression is bad i will prob pull the motor and use another block that i have and just rebuild and start over.

 

[tigger_tat_55]

well the air flow meter checks out.

went thur the vacum lines again, still did not find anything.

compresion: 1. 136 psi 2. 139 psi 3. 145 psi 4. 130 psi.

book says min is 142 psi with a diff between them no more than 14 psi
and says norm is 172.

have been able to get it to run better in the upper range, still misses down low and at idle have no idea what i did.

going to check the egr in the am.

with the above numbers on the compression, going to start looking for a rebuild kit. after the egr check if that is ok, prob just run it till I get the other block ready to go.

thanks for all the help and info you guys are great!!!!:tounge_out:

 

[tigger_tat_55]

got a block, just need to pull it out of the parts truck and get going on it.

went thur the egr, as well as all the rubber lines again. checked the vacume at intake manifold, all checkd ok.

question: will the low compression make it miss/surge? and why does it do it mostly when its cold??

replaced the coil just because, did not notice any real change.

not sure bout the cat, havnet really messed with it....yet.

wondering if I should just save my time/money for the rebuild??

 

[tigger_tat_55]

went at again this evening.
thot what the heck, got beer, got cigars...wife is at a meeting....why not.

went back thur and did another compression check. found the numbers where the same...this time put a bit of oil in there to see if it would raise the numbers....it did'nt. hhhmmmm

so rechecked the valves...they were right on...hhhmmmm

went ahead and opened them up. intake to .010 and exh to .014 then reran the compression...what a difference. got 150 across 1,2,3 with 4 being 140. put oil in it and it came up to 165..... idle is good again have power back. no more miss or surge.....

looks like i will still have to deal with number four at some point. but for now I can drive it again and will deal with it at a later time.

I would like to thank all of you that helped out. I gave me places to look that I had not thot of.

again thanks to all.


TW


ps...nothing is impossible with the right amount of beer/cigars...