98 Rodeo Engine trouble again

Up until July my (V-6) Rodeo was running great. However, one day I went to start and it began shuddering and would barely run…I had to tow to dealer. It had jumped timing, $1200 later (they replaced numerous parts before realizing it was timing) it ran great again. 3 weeks ago when starting, it was difficult to start, idled up and down, and would stall when slowing. Also, was sluggish running. Took to dealer again, and again they began replacing parts…O2 sensor, throttle something. The codes they got were: P0123, P0122, P0121, P0151, and P01640. They also ran a compression check and got 25 on number 1, 50 on number 3, and 60 on number 5. The mechanic sprayed cleaner on left side, the side with low compression but said he did not notice an increase in idle. This went on for over 2 weeks and they finally said I needed a new engine!!! The Rodeo ran great to this point, 110,000 miles, only burned 1 quart of oil every 5,000 miles. I can’t believe I have to replace the engine. I would think it would not run at all if this were the case. What could be the problem? I need help!!! I can not afford to either replace the engine or total the vehicle, which is in great shape otherwise. Any help would be greatly appreciated.

My guess is that if it did jump timing then there may have been some valve damage due to hitting a piston (this is an interference style engine). If the valves are damaged that could explain the low compression. All that may be needed is a valve job on the damaged side.

+98 Isuzu are non interference.

I was informed by the Isuzu dealer that last replaced the timing belt that it was an interference engine. There is alot of debate about which one it is. Here is a site with some more debate, an one of the replies
makes a statement that being an interference engine means that there is the possibility of valve damage not a certainty.
http://www.automotivehelper.com/topic325554.htm

However, it still seems that there is a valve seating problem in those 3 cylinders

Hang on folks.. Here we go round & round again!!! :rofl: (j/kidding!) The 1998+ 3.2/3.5 engines are classified as 'interference' by isuzu. There have been several posts now where 1998+ owners have had the T-belt pop off on the fly with no ill effects. There have also been posts where owner's replaced the T-belt, had the valve timing way off & had no problems at all once they set the timing properly. My bet is these engines are REAL close to being smashers so isuzu calls them interference to cover their butts. DCNavy, given the fact that your truck ran great for 3 weeks after the original valve timing issue, I'd say it didn't smash. Why your truck jumped time again is a mystery. Do you know if they replaced the t-belt tensioner/pusher??

G/luck
Joel

I would get the repair sheet stating what parts they have replaced etc.

IDLE is usually controlled by an IAC (Idle Air Control solenoid). If that is not working right then you will have IDLE problem. Try removing the IAC and clean the spot where the IAC goes in. Try cleaning the IAC and re-use it and test it.

Check your EGR and clean the passage way to the intake and at the exhaust side of the EGR.

Check for any vacuum leak.

Thanks for all your help. I drove it again today to take to another mechanic (non-dealer), funny how it will cruise along at 70 mph (runs smooth), but around town and in low gears it acts crazy. It dies at traffic lights unless I use creative gas work. If rings/compression are bad on R side would it run like this? Was told that timing is right. Where is the IAC located? The dealer replaced a switch…throttle body something...along with the O2 sensor. One other note, I have noted loss of coolant for a few months now…1 gallon per 1-2 months. Did note yesterday that coolant has pooled on engine below head. No water in oil or oil in radiator though. Interested in what this mechanic can find. I felt as if the dealership just wanted me to get the truck out of their garage.

IAC is usually located on the throttle body. You could be slowly loosing water through the water pump weep hole. Water drips in the weep hole is a sign that the water pump needs replacement soon.

hey DCNavy,

my past experience was this. the following was over a 2 month period.

98 rodeo 95k:
rpm erratic - high (2k) and low (500) at start
rpm idle very low 500/1k
began stalling out on colder start- low idle
stalling while driving on rare occasion.
no power, pedal to the floor and doing 10 mph

mechanic:
replaced 3 IM gaskets
new sparks (ngk laser plats)
cleaned EGR (produced CEL previously- 5 mo earlier)
hand clean intake ports (very dirty, had to soak overnight)
motorvac fuel clean service
clean carbon and varnish from fuel line and throttle body assembly, intake valve and combustion areas
$1000

2 days later same problem.

back to mech:
they stated on phone that 'it’s probably residue from the clean'
pick up from mech: stated they cleaned some part that was near the fuel line

I can't recall what they cleaned as they did not charge me the second time and I did not write it down but it runs alot better now, more power than before.

I'm not mechanically inclined when it comes to cars so I can't offer advice but stay on the forums, get the advice and maybe direct the mechanic as what you want checked

Is the coolant you see pooling under the side of the engine head that is supposed to have the low compression?

Here is my two cents, lol.
Running good at cruising speed, but dying at an idle, usually states a vacumn issue somewhere, or a sensor, like was previously mentioned.

Jumping time, again....Different car alltogether, but I had a 1962 VW bug once and the flywheel came off while I was driving it, and stopped the engine suddenly. I fixed it, put it all back together and it ran fine for two weeks, then it would not fire correctly.
After long frustrating hours, I pulled then engine again, starting checking things out, and found that somehow the crank had developed a crack (probably due to the sudden stopping), and it had cracked just enough to keep the car from timing correctly, ever again.
It may not mean anything to you, but if you think if the flywheel as your timing belt, and the crank as the crank, think what happens when that valve train suddenly stops on these everhead valve engines.......
Just my thoughts.
John

hey DCNavy,

my past experience was this. the following was over a 2 month period.

98 rodeo 95k:
rpm erratic - high (2k) and low (500) at start
rpm idle very low 500/1k
began stalling out on colder start- low idle
stalling while driving on rare occasion.
no power, pedal to the floor and doing 10 mph

mechanic:
replaced 3 IM gaskets
new sparks (ngk laser plats)
cleaned EGR (produced CEL previously- 5 mo earlier)
hand clean intake ports (very dirty, had to soak overnight)
motorvac fuel clean service
clean carbon and varnish from fuel line and throttle body assembly, intake valve and combustion areas
$1000

2 days later same problem.

back to mech:
they stated on phone that 'it’s probably residue from the clean'
pick up from mech: stated they cleaned some part that was near the fuel line

I can't recall what they cleaned as they did not charge me the second time and I did not write it down but it runs alot better now, more power than before.

I'm not mechanically inclined when it comes to cars so I can't offer advice but stay on the forums, get the advice and maybe direct the mechanic as what you want checked