Just wondered if anyone could help with this thing. Several years ago we replaced the 350 in our '89 3/4 4x4 with a brand new 350 Chevrolet engine (the old motor was burning a lot of oil). This new motor runs ok, but just doesn't seem to have the same old "guts" the old one did and after 15-20 min. you get a "service engine soon" light and it smells like rotten eggs/skunk all of a sudden. The harder you drive it and pull it the better it seems to run and it won't code. I've gotten the codes a long time ago and I think they were the emissions code, took it in to Chevy and they put it on their computer, said they got it fixed . . . still does the same thing. Does ANYONE have any idea? I had one mechanic tell me there is a port in the intake manifold somewhere that is suppose to advance ignition or pull vacuum when you hit the throttle that probably is plugged up with oil off of the old motor. Another mechanic told me that was a bunch of bull. I'm about just ready to drive the thing with the light on and just forget it. Its just sad to get a new 4 bolt main motor and have this crap go on. Thanks

It might be an o2 sensor. Get the code for us and it will help a lot.

Could be a clogged catalytic converter.

Also check the little hard pipe that sends vacum to the egr valve. They are brittle after ten years and crack very easily when handled during the swap. If it leaks it wont run right and will throw a code. I typically replace all sensors including the egr valve when replacing the engine. If you do fing that little hose cracked or broken you can repair it by breaking it in two and sliding a piece of appropriately sized shrink tubing over it and heating it to fit. Be sure you have the orientation correct of the two ends so it will line up correctly when re-installed.

You can read the codes yourself by jumping two of the terminals in the adl port under the dash. I forget which two and no longer have the book. It will flash the check engine light in sequence to read you the codes. In other words... flash flash... pause... flash flash... is 22. Maybe you can search that on the internet for the exact method.

Here is the egr without the hose on it...

The O2 sensor I replaced and thought I had it fixed . . . didn't help. The line I'll look at in the morning and see if I can find any cracks or breaks. The catalatic convertor I thought about and had it checked at a muffler place for backpressure . . . nothing wrong with it at all. Weird!

Make sure all th eelectrical connections are made including the spark advance one at the firewall. Its a single wire connector... brown.

Go here for instructions on how to read your codes yourself...

http://www.kennedydiesel.com/readcodes.html

Let us know what codes you have

Ok, the codes that came up are 32 . . . EGR Circuit code. Now what does a guy look for? I checked the line running to the EGR valve and it SEEMS ok. Any more thoughts?

Which engine you use, basic Goodwrench 350 or the one specifically for your truck? Reason I'm asking is that cam may be messing with ECM. Rotten egg odor is usually caused by running rich, but could also be convertor or the fuel, some gasolines have a bit more sulphur than others. The old TBI throttle bodies are prone to coking in the vacuum passages,usually the PCV passage first. There's also an EGR solenoid in line with a little filter inside that clogs. Vacuum goes from TBI to solenoid then to EGR valve. It's manifold vacuum to solenoid. Also make sure MAP sensor has good vac hose to it. And no vac advance,all electronic

Wait wait! Slow down some for me! The old engine was a 350 and thats what I specifically ordered from GM was another 350, not rebuilt but brand new. The new one is a 4 bolt main . . . I really don't know if it was exactly like the other or not, I told them when I ordered it I wanted a heavy duty 350 engine for torque due to it being on the farm/ranch.

I don't know if you read the other posts or not but GM messed with it and thought they had it fixed . . . they didn't. I had the converter checked to see if it was plugged . . .its not. The code was a 32 which is the one its given me from day one. I'm so used to diesel power now this pickup used to scream but just doesn't have the balls it should have, you can't HEAR the motor pulling under load, its just quiet (anemic). Then theres the rotten egg/skunk smell after about 15 min. of driving (won't code near as easy when loaded). I had a mechanic tell me something about a passage maybe getting plugged from all the oil from the old motor but another told me there was no truth to that. Anyway you had to remove the intake to check it so I never have.

What specifically would you look at (give it to me simple as you can), I've looked at the EGR valve and line and can't see any cracks. Where specifically is this tiny filter and this passage your talking about? Do these symptoms sound like it could be these? And what do you do in laymens terms?

By the way, this is a TBI. Are all these passages and lines where I can visibly see them or are they built into the intake? If they are "coked" up then do you have to replace the intake, if so, would you go back to stock.

I have no idea about the cam!

Thanks much!

I would double check anything to do with the egr valve. Mine did exactly the same thing. That little hose can be cracked but you may not see the crack. Trust me if it leaks you'll get the egr code. Maybe the egr valve is bad. There also is a valve that controls it. The unit the the little hose hooks to. Make sure all elec connections are correct.

89 did not originally come with the four bolt main.

i would go up to napa and get a TBI rebuild kit. i just sold my 89 350 to buy my 03 so i am familiar with the engine. the TBI rebuild kit is only like $40 and contains all the gaskets o-rings and everything you need. a couple bolts takes the whole TBI off. tear it down and clean everything. you would be amazed at how much buildup there is. it should also include a new fuel pressure regulator. there are lots of vacuum ports inside the TBI and when i rebuilt mine @ 210k miles, half of them were completely clogged. i cant believe it still ran as good as it did and got 13 mpg! i would do that and replace the vacuum hose to the EGR and see if it fixes it. there really isnt much in the EGR to go bad so the problem is probably in your TBI.

Easy way to check for TBI coking is to remove vac hoses from TB one at a time. If there is vacuum then you're fine. The filter is in the top of the EGR solenoid. At the top is a round cap which you can remove, it snaps off. Soap and water will clean it, make sure it's dry before reinstalling. Make darn sure MAP sensor hose is good as the ECM looks at the sensor voltage to see if EGR is working. If any vac passages are clogged remove entire TBI and clean them out, I use small screwdriver to clean most crap then spray carb cleaner through passages

I haven't got to check on the vac. hose or anything yet, but one question: Taking the TBI off is not big deal? No springs to shoot out or anything? I've never taken one off before, but as I understand 2 bolts take the whole shooting match off? I'll check on the rebuild kit, what do you do lay it out on a white towel and start taking stuff apart and cleaning, then just reassemble? Lordy that sounds scary!

yea its really not bad trust me! the only thing that has a spring is the fuel pressure regulator, but the rebuild kit (at least mine i got from NAPA) had a whole new regulator so i didnt have to take the old one apart, just off. its an amazingly simple unit (which is why i love my 89 compared to the new motors you cant hardly work on yourself). the injectors just unclip and come out and basically youre just left with a chunk of aluminum with passage ways all through it. use some stiff wire or a small screwdriver like someone said to knock out clogs in the passages.

im pretty sure a chiltons or haynes manual shows how to do it with pics so you can pick one up (if you dont have one) and check it out ahead of time so you know what to expect. its really not bad though, trust me.

If passages are clogged TBI will not have to come totally apart. All you have to do is pull complete unit off and clean the passages, only part you need will be a TBI mount gasket. Only reason to dissassemble unit is if regulator is bad or an injector goes bad

you are correct in that its not needed. i disagree that there is no reason to. i only suggested doing since its cheap and after 15yrs, the TBI could use it. you dont really notice the gradual loss of power and fuel mileage over time. i couldnt believe how bad mine had gotten when i did it. 15 years and 200k miles is a lot of build up.

200k is just geting broke in... only thing I've seen go bad in older TBI units is the throttle shaft wallers out the throttle body. Think in all my years working on these units number of injectors I've had to replace can be counted on one hand, this goes back to when chevy started putting them on the 82 A and X bodies with the 2.5 engine. Man what fires we had back then, we had no clue how to work on them(until yours truly got the short end of the stick and had to go to GM training for them)

200k is just geting broke in... only thing I've seen go bad in older TBI units is the throttle shaft wallers out the throttle body. Think in all my years working on these units number of injectors I've had to replace can be counted on one hand, this goes back to when chevy started putting them on the 82 A and X bodies with the 2.5 engine. Man what fires we had back then, we had no clue how to work on them(until yours truly got the short end of the stick and had to go to GM training for them)
What a simple and reliable system it truly was/is.