Does anyone here tinker with cars?

[Cliffhanger]

I have a truck that will sort of crank, but it won't stay running, even with the throttle wide open. There's a transmission waiting for me at the shop, and I've been trying for three weeks now to get the beast cranked. If anyone's interested, I'll tell you what all I've done.

 

[maroonedinhsv]

You are going to need to provide a LOT more info before anyone can help. What you’ve already checked would be good, but make and model along with engine would be really beneficial.

 

[Cliffhanger]

Oh, I know. I just didn't want to type it all out, if no one was interested. I'll type it all tomorrow, when I'm on an actual keyboard. There's a LOT.

 

[Cliffhanger]

1995.0* Isuzu Rodeo** 3.2L SOHC with automatic transmission and 4WD

*They redesigned the truck in the middle of the model year, switching from OBD-I (which is what I have) to OBD-II, and changing up the interior to add airbags. When I buy parts, I order 1994 parts to make sure I get the right things. I haven't yet found any differences between the 94 and 95, but there are a LOT of differences between the 95.0 and the 95.1 (my numbering system).

**AKA Honda Passport

It's been parked for two years, but it cranked and ran fine in Jan or Feb. Needs a transmission, so once I was finally able to afford a pull-off, I bought one and had it drop shipped to my transmission shop. Now the truck won't run. The only thing I did to it between when it last cranked and when I tried to crank it to drive it onto the rollback was that I put a new battery in. I'm thinking that may have reset one or more codes it may have had.

It was a beater when I bought it, not taken care of at all, and my friend and I nursed it back to health. It ran great for a little over a year. Then the rear dif blew on the interstate. Got that replaced, but it damaged the transmission. Started losing power, wouldn't come out of first gear, even with the pedal on the floor. Almost didn't make it over the hill to get home the last time I drove it. Engine idled fine, just no power. So I parked it, intending to save up for a transmission. Things happened, and it took two years to be able to buy one. Now the transmission has been sitting at the shop for three or four weeks, and I can't get the stupid engine running. It'll crank, but it won't stay running, even with the throttle wide open. And it smells like gas. When I hold the throttle open, the engine pops at a steady rhythm, running very roughly, and it stays below 500 rpm, instead of running smoothly at 800 rpm like it's supposed to. Soon as I release the throttle, the engine sputters to a stop.

Here's what I've done since swapping the battery: Checked and topped off the engine coolant. Checked the oil level. Added six gallons of fresh gas (E10, 93 octane) to the tank, along with some enzyme additive (tank had ethanol-free fuel when parked, and was almost empty). Pulled the aftermarket short ram cold air intake off and partially reinstalled the OEM intake, replacing the return hose in the process, but leaving the cone K&M filter at the end of the intake, instead of reinstalling the breather box. Pulled, cleaned, and reinstalled the idle air control valve. Pulled, cleaned, and reinstalled what I think is the vacuum control for the EGR. Replaced the TPS, after getting nowhere with attempting to probe test with a voltmeter the one that came off. No changes after doing each of these.

Here's what I think may need to happen, based on hours of looking online for answers: Pull, inspect, and either clean or replace the EGR (couldn't figure out how to do it yesterday, and neither the Haynes nor Chilton book was helpful). Find and replace the engine coolant temperature sensor. Pull and inspect each spark plug (I'm apparently not strong enough to do this one on my own, I tried). Maybe pull and replace the crankshaft sensor, if I can find it (I think I gotta pull the wheel to do that, if I'm able to). Rebuild the rather leaky exhaust from the back of the Y pipe to the resonator tip (can't do that until I take it to a pipe shop, and I can't do that until it runs). These are the things I've seen suggested to people who are having the same problem I am.

I'm getting really frustrated at spitballing for solutions, and I almost want to roll the truck across the scales, but I've put so much time and effort and money into it, I'm not sure if that's the right thing to do. Plus, it's a tough little truck. Metal bumpers, no plastic on the body at all. You just can't find those anymore. I work two jobs for a total of six days a week, so I only get one day a week to work on it - if it doesn't rain. And I'm not sure how much longer the transmission shop will be okay with holding onto my transmission for me.

Help?

PS, I'm not a mechanic, I've just been learning about fixing stuff on the truck by watching my friend work on it, and Googling, and watching YouTube videos. My friend moved to another state while the truck was parked, so I'm on my own with this now. :-(

 

[maroonedinhsv]

Plugs seem possible, but I’m not sure how well that aligns with the gas odor. I’ve seen similar behavior with clogged fuel filters and bad fuel pumps. Could be fuel injectors or many other things down the fuel supply system. Have you tried doing detective work with your nose to see where the gas smell is originating?
Edited to add: did you pull any codes prior to changing the battery?

 

[Cliffhanger]

I have anosmia (not Covid-related), so I'm only getting faint hints of gasoline smell, when I do get them. I'm afraid it would be near impossible for me to actually trace the source of the smell, when I can't tell how strong or weak the smell is, because I only have the ability to detect an odor, but not the strength or direction of the odor. (That's why I don't have any natural gas appliances - most of the time, I wouldn't be able to smell a leak.)

Should I try replacing the fuel filter? I don't have enough engine knowledge be able to take it apart down to the fuel injectors. I can only do basically the sensors and things that I can see up on top or on the side or underneath.

 

[Cliffhanger]

It's been awhile since I've jumped the pigtail and pulled the code, but the last codes I remember were the O2 sensor, which I have replaced, which did not clear the code, and something to do with air flow or air pressure. I really wish I had kept a journal when working on this truck over the years. It is now showing no codes at all, other than the number 12 handshake. I'm assuming that's because the battery was pulled and replaced, and now the engine is not able to run long enough for the computer to diagnose.

 

[maroonedinhsv]

I have anosmia (not Covid-related), so I'm only getting faint hints of gasoline smell, when I do get them. I'm afraid it would be near impossible for me to actually trace the source of the smell, when I can't tell how strong or weak the smell is, because I only have the ability to detect an odor, but not the strength or direction of the odor. (That's why I don't have any natural gas appliances - most of the time, I wouldn't be able to smell a leak.)

Should I try replacing the fuel filter? I don't have enough engine knowledge be able to take it apart down to the fuel injectors. I can only do basically the sensors and things that I can see up on top or on the side or underneath.

I don’t think I would randomly replace the fuel filter unless you think it needs it anyway. I would get some help trying to find the source.

 

[Mike S]

I'm no mechanic, but it almost sounds like a fuel pressure regulator issue. Just a WAG on my part.

With all the money you are considering throwing at it in parts you could probably have it towed to a reputable shop and pay them to diagnose it for you.

 

[Cliffhanger]

I may end up doing that. I'll have to see how finances go.

Edit:
I just don't want to get "taken," especially since I'm female, and it's an old truck. That's why I'm trying to fix it myself, if possible. Plus having the satisfaction of having done it myself, or with help, instead of paying someone to spend hours on diagnosis and repair. I'm just super frustrated with the two halves of me pulling either direction ("pay someone else to do it" <---> "do it yourself").

Another edit:
I just reread your post, Mike S. You said "diagnose it" not "fix it." I missed that. Sleepy eyes.

 

[Evan]

You might also consider a mobile mechanic if your budget is limited. Try to find one who is familiar with your engine type or has worked on similar vehicles in the past. A lot of mobile mechanics do great work for a fraction of what you'll pay at a shop.

That said, you have to properly screen to make sure you get someone decent. Trust your gut. Have a small list of questions you plan to text or ask when you call. If someone makes unrealistic promises then move on. If you find someone willing to come out for $40-75 to spend 30-60 minutes to try to diagnose, and they seem knowledgeable and credible, then it may be worth a shot. I've saved a lot of money using mobile mechanics when it was a project I didn't want to deal with.

It's an old enough vehicle that any decent mechanic should be able to figure out the root cause fairly quickly unless it is something odd and esoteric. Remember, spark, fuel, air and compression are the four keys. I think your issue is most likely to be related to fuel or compression from what you indicated in your previous posts, but I'm not a mechanic so my guess is simply that.

I found three threads that have people discussing problems similar to yours. At least one of the threads is multi-page, so make sure you click next and read the next page. Lot of good diagnostic info (even some diagrams and step-by-step troubleshooting info) in the threads.

Engine Is Not Starting: I Have a 1994 Isuzu Rodeo with the 3.2L V6...

I have a 1994 Isuzu Rodeo with the 3.2L V6. It has been sitting for quite some time and now I can't get it running. I have replaced the Fuel ...

www.2carpros.com

My Engine Won't Start Up?: the Car Is in the Park and the ...

The car is in the park and the weather is very cold, it cranks but it wont run? Reply 1: This sounds like a fuel pump or the crankshaft angle sensor ...

www.2carpros.com

1995 Isuzu Trooper Won't Start/run?: Just the Past 5 Days My Car ...

Just the past 5 days my car was running rough just after starting in movement in 1st & 2nd gear then after a few minutes it was fine. It wasnt ...

www.2carpros.com

I think it's worth reading each thread -- at worst you'll eliminate some potential causes or pickup the next diagnostic steps you need to take. The one post about the timing belt stood out a bit to me -- does your model have a timing belt and is it in good shape? It sounds like you have checked spark somewhat already, but the last link I posted above has a quick and dirty way to verify spark. Once you do, you have a few quick things you can check on the fuel side. But, if it were me, I'd double check the timing belt before doing anything else. Just to make sure!

 

[Cliffhanger]

Thank you! I don't believe these threads have come across in my searches (you know how Google loves to change search results based on algorithm). I'll read those tonight, and see what I can find out. I like the sound of the mobile mechanic. Do you have anyone you feel comfortable suggesting? (PM is okay.)

The timing belt was replaced when the major work was done a couple years ago, and the timing was reset manually, using the notches. I watched my buddy do it. It's had maybe 15,000-20,000 miles driven on it since then.

 

[Evan]

PM sent.

 

[Cliffhanger]

Got it running! Fires up on the first try now, and runs more smoothly than it ever has.

Of course, when I was under it to change the oil to get it ready to go to the transmission shop, I noticed that the front differential breather valve broke off at some point, so now I have to go hunt one of those down and replace that.

 

[Mike S]

so what was it?

 

[Cliffhanger]

I completely redid the intake and reinstalled it with new clamps (it's now partially OEM - the previous one I had installed was completely aftermarket), replaced a return hose, replaced the air cleaner (which wasn't all that dirty, but I did it anyway, using a smaller one) with new clamps, replaced the cleaned-out idle air control valve because I suspected it was still sticking (and it turned out to have a damaged gasket that it didn't previously have [my bad]), and replaced the throttle position sensor. So it was one of those.

 

[Cliffhanger]

My planned next step was checking spark, then fuel, then vacuum. Figured I'd go from easiest to hardest, starting with air, and hope it was something easy.

 

[Mike S]

I completely redid the intake and reinstalled it with new clamps (it's now partially OEM - the previous one I had installed was completely aftermarket), replaced a return hose, replaced the air cleaner (which wasn't all that dirty, but I did it anyway, using a smaller one) with new clamps, replaced the cleaned-out idle air control valve because I suspected it was still sticking (and it turned out to have a damaged gasket that it didn't previously have [my bad]), and replaced the throttle position sensor. So it was one of those.

I didn't even think of this before, but after reading the initial concern I'd almost bet that the idle air control valve was the problem.

 

[Cliffhanger]

That's what I'm thinking, because last night when I posted, I didn't realize that I had already replaced the throttle position sensor and part of the intake by the time I made my initial post. Between the idle air control valve and the new clamps and smaller filter on the intake, it seems like maybe it's not gulping so much air now, which would have explained the fuel smell. I imagine it was dumping fuel into the cylinders to compensate for having too much air. The engine does not have a MAF sensor, but it does have a MAP sensor.

 

[Cliffhanger]

Oh, and I want to say Thank You to everyone who chimed in and gave advice! I got more help here than I did in the Isuzu forum, where I got exactly zero replies to my thread.