02 Alero V6 mystery engine problem (3500) [Archive] - GrandAmGT.com Forum

PDA

View Full Version : 02 Alero V6 mystery engine problem (3500)


over's ga
12-26-2012, 03:15 AM
UPDATE/ SOLVED . IT WAS CATALYTIC CONVERTER.......
-----------------------------------------------------
...mystery to me, probably just a sensor or something obvious. Please help with diagnosis

3500 engine swap just done but I don't think issue is with swap.

(NO Check Engine Light lit)

Problem. low power driving, runs rough at times, slow response with rev limiter like cut out while revving in neutral, no service engine light (light works) car starts right up and idles normal, starts to idle a little rough after running for a while, driving it has very little power and won't rev and shifts erratically

CAR HISTORY:
2002 70,000mi. Alero, bought cheap with seized/rusted tight 3400, sat long time with water in cylinders, gas was stale (may of been sitting for 3 + years!)

-Did '06 low mi. Malibu Max 3500 swap with Milzy kit (just basic swap, re-used 3400 fuel rail/injectors, upper intake/tb, all sensors, etc. except temp sensor)

-I had done identical 3500 swap with Milzy's kit on a '04 Grand Am that worked out great, did nothing different on this one and re-checked all of swap specific stuff.

-New fuel pump module & filter, (I wonder if I got defective pump)

-cleaned stale fuel out of lines & cleaned original Alero fuel rail/ injectors as well as I could

......What I suspect: clogged catalytic converter, stuck/ bad injector, bad sensor/elect engine control part
...don't really know how to test above, I want to try testing cat by loosening head pipe nuts (leaving gap) to let exhaust out before cat and take for short drive

AaronGTR
12-26-2012, 06:50 PM
Double check the external crank trigger. I know some people have had issue with the engine running right when doing that swap because they didn't have the gap adjusted just right.


Other than that... with how much work you did and how much stuff got replaced, it's hard to narrow it down to any one thing. You have no idea what was good before hand and what wasn't. Could be the cat. Could also be bad/dirty injectors or a problem with one of the sensors. Time to start cleaning stuff and checking anything you can. Run some fuel system cleaner, clean the MAF sensor, make sure the vacuum lines are all tight and no cracks, etc.

over's ga
12-26-2012, 09:21 PM
I readjustment crank trigger once after talking with Milzy. No change. I may try some different gaps just to see.

I'll try some fuel treatment/cleaner, all vac lines look good but I got to recheck everything, also want to put stethoscope to each injector to here them clicking.

Not tripping the light has me a bit lost. THANKS for input

over's ga
12-28-2012, 05:37 PM
It was the cat!

I pulled down the head pipe after loosening nuts almost all the way out, took for a loud test drive and its got balls now :cheers::cheers:

just got to find cheap replacement

over's ga
12-28-2012, 05:46 PM
any ideas, on budget cat replacement??

I can get just universal new cat and weld in place or spend quite a bit more and get complete cat with pipes to bolt in.

I have a mig welder and can do universal, but I thought it was stainless steel? can I weld with regular mig wire to that pipe and new catalytic converter?

sleepyalero
12-28-2012, 06:08 PM
Have Milzy make you a custom no cat pipe he did one for me for like I forget... 125-175 or something...

over's ga
12-28-2012, 06:21 PM
I'm in Az, I need to pass emissions before it can get registered, thanks though

AaronGTR
12-29-2012, 06:04 PM
any ideas, on budget cat replacement??

I can get just universal new cat and weld in place or spend quite a bit more and get complete cat with pipes to bolt in.

I have a mig welder and can do universal, but I thought it was stainless steel? can I weld with regular mig wire to that pipe and new catalytic converter?


Do you have a stock down pipe? That is not stainless. It's just regular coated steel. You can weld a universal cat to it with normal MIG welding wire. Just get a decent sized high flow cat. You don't want to go cat-less anyway. They sound like crap without one, smell bad, and pollute. Plus there isn't much power to be gained over a high flow.

over's ga
12-30-2012, 02:47 PM
I decided on bolt in direct fit, found good deal online for $135 shipped

http://www.usautoparts.net/catalog/index.php?N=11412+4294962955+1686+11921+9190&Ns=price2%7C0&Npp=10

on the universal ones, yes I guess the cat itself is stainless but the tubes are more a mild steel. I could of done it but I'm feeling lazy, any welding and fab work I want to do on my jeep

unchained_01
12-31-2012, 01:56 AM
Plus you should see how much you can get for your old one. Recycle it. Some bring decent money

over's ga
12-31-2012, 02:34 PM
Thanks for reminding me, I go to metal recycler a few times a year

over's ga
01-15-2013, 12:15 AM
just wanted to close this.

...Got the new ready fit cat installed & the car runs like it should, what a difference!

-everyone says service engine light should of been on with bad cat, didn't apply here.
-using a IR temp gun didn't show cat was bad (according to online guidelines)
-auto trans shifted as if trans was bad with clogged cat, shift fine now.
-even under hood idling you can tell it is flowing free compared to before.
-don't forget diagnostic trick of loosening cat pipe nuts a bit to check if it runs better

MilzyZ34
01-15-2013, 09:29 AM
Do you have a stock down pipe? That is not stainless. It's just regular coated steel. You can weld a universal cat to it with normal MIG welding wire. Just get a decent sized high flow cat. You don't want to go cat-less anyway. They sound like crap without one, smell bad, and pollute. Plus there isn't much power to be gained over a high flow.

i don't think it's that bad without a cat. the biggest thing is i take comfort in knowing it will never clog again if i delete the cat. power gain over a highflow depends on mods, but it can be a good amount.