89 ranger spark knocking badly

[cn.anglin]

ok i have a 89 ranger 2.3 8 plug truck.i bought it as a running project 2 years ago for my son when he turned 13. we did alot of brake work,tune up,exhaust,shocks etc. it has never left the yard since i bought it.put tags and insurance on it for my son took it down the road and wasnt sure i was going to make it back it was spark knocking so bad. had a spare icm but that didnt help. timing belt looks good{havent actually checked the timing yet}.coils are good.truck cranks right up and idles perfect but under acceleration it runs horrible. it has a new fuel filter and air filter also.also has good fuel pressure at the port.any ideas would be great.i am going to replace the timing belt next week anyway so maybe it has jumped

 

[cn.anglin]

pulled timing cover off.appears someone put a new belt on before i got it.if the engine is at tdc the cam sprocket pointer is at the top of the engine and should be at the bottom.how do i make 100% sure i have the engine on the compression stroke? i can feel the piston at the top of the cylinder.

 

[Mark_88]

You can take out the plug, put your thumb over the hole and crank the engine manually...disconnect the coil wires or the battery ground before doing this...once you feel pressure on your thumb you will be in the compression stroke...

To see if the piston is at the top of the cylinder you can shine a light in the hole and should be able to see the top of the piston...slight back and forth motion will allow you to check where it is...

 

[Insanejughead]

pulled timing cover off.appears someone put a new belt on before i got it.if the engine is at tdc the cam sprocket pointer is at the top of the engine and should be at the bottom.how do i make 100% sure i have the engine on the compression stroke? i can feel the piston at the top of the cylinder.

Hahahahaha! Yep, that's your problem.


The cam sprocket pointer needs to be at the 5 o'clock position for the engine to be timed properly.


I say, take your timing belt off.

Align crankshaft according to it's timing mark by slowly tightening the crank bolt (doing it slow keeps it from getting TOO tight).

Then, by tightening the camshaft bolt, turn the sprocket until the alignment mark matches up with the middle pointer on that back part of the timing belt cover.

Don't worry about aligning the auxiliary shaft sprocket. It doesn't turn anything except the oil pump on the '89-'94 model years.

Now install the belt. Once you get the grooves lined up on the crankshaft sprocket, pull the belt tight and get the grooves seated on the auxiliary sprocket. Now pull tight (but not enough to turn the engine, haha) enough and seat on the grooves of the camshaft sprocket.

Then loosen the tensioner and let it take up the slack.

Now comes the most important part. Double checking the correctness of the alignment marks. I like to do this by, again, tightening the bolt on the crankshaft slowly. Do two full turns of the crankshaft and see if the camshaft and crankshaft marks line up to their indicators. If they do, GREAT! If they do not, then you will need to adjust the belt by one notch on the camshaft. Repeat the test. If they line up now, go to the next step.


Now you can put everything back together.

Oh, and be sure to tighten the tensioner bolt down, so that the belt cannot get slack if you rev the engine too much, and consequently jump a notch.





Last, but not least, let us know how it goes!

 

[cn.anglin]

yea i took the belt off,made sure the piston was at the top,aligned the cam with its notch and put it back on.before i could finish it started raining .going to try and finish it tomorrow.pretty sure that was the problembut ill let everyone know for sure.i have replaced a timimg belt on my 92 2.3 ranger years ago but it had broken first and i didnt even think about just taking off the belt and aligning everything.thanks for the idea

 

[cn.anglin]

well it still runs like s@#t.starts up better and idles great.as soon as you take it over 15 mph it spark knocks and bucks so bad you can barely drive it. the timing is perfect now.is it possible it could have bad injectors? at this point i am lost.somebody please help

 

[Mark_88]

This is what mine did EXACTLY when I first rebuilt the motor. Mine is carbed, of course, but they do run similarly...I farted with timing and plugs, wires, and even distributor cap and all that...

It turned out my carb had a vacuum leak at the base of the carb...it would idle nice and run great...as long as I didn't try to rev it up...

So...take a can of brake cleaner or other fluid and spray around the intake...gently...if you hear a slight rise in the RPMs at some point you will have found a very distinct vacuum leak...

If that doesn't work...or proves fruitless...you may suspect things like the computer that controls timing advance...

 

[BRUTUS_T_HOG]

well it still runs like s@#t.starts up better and idles great.as soon as you take it over 15 mph it spark knocks and bucks so bad you can barely drive it. the timing is perfect now.is it possible it could have bad injectors? at this point i am lost.somebody please help

What is the fuel pressure while under load? Try running it without the SPOUT shorting bar

 

[cn.anglin]

i will check for vacuum leaks tomorrow.thanks for the idea. i did find 2 plug wires crossed but that didnt fix it.it idles fine and you can rev it to about 3000 rpm in neutral before it starts missing and the tach bounces.as soon as you put a load on it it starts acting crazy. i suspect i have bought somebody elses problem they couldnt fix.i have had several of the rangers over the years and i will figure it out

 

[cn.anglin]

unsure of fuel pressure under load but it is @32 at idle

 

[cn.anglin]

as far as fuel pressure i just checked it again.it goes to 32 when you cycle the pump and then drops to about 26 at idle.give it gas and it jumps to 36-38 and then drops down to 26 where it stays even at wot which the engine starts trying to cut out at 3000 rpm. i did find a broken vacuum line and i replaced it but it didnt help.so am i still looking at an ignition problem or is there something wrong with my fuel pressure readings? thanks

 

[scotts90ranger]

Unplug the MAP sensor and see how it runs... It's the 3 wire connector that plugs into a module that's recessed in the firewall on the passenger side just above the heater motor, has a vacuum hose going to it.

Actually, before you get that far, have you checked for trouble codes?

 

[Mark_88]

Does sound a bit low...but from what I've read the pressure should be 35-45 or higher...

 

[cn.anglin]

have not checked for codes.the check engine light is not on.yea i thought the fuel pressure might be a little low.

 

[BRUTUS_T_HOG]

26psi is too low. Should be more like 40-45 at WOT. I think you also have a problem with the ignition module or crank sensor because the tachometer cuts out.