Just bought an '88 IROC convertible. The dealer swapped the engine before I even saw the car. They got some sludge in the oil pan when replacing a gasket and it was sucked into the oil pump....or so they say. At any rate, they swapped the stock 305 TPI with a rebuilt 350 TPI. Engine is having intermittent problems with overheating. Stays cool at speed, but when idling, the temp will slowly build until it starts to boil .

Both fans are working...I don't know if they kick in at the proper temperaures. I bought the car from them 6 days ago and I have had it at home only 2 days. Been back up for them to 'fix' stuff since then.

The dealer took it to a shop that said the stock 305 radiator would barely keep the 305 cool, let alone keep up with the 350...any truth to that?

The water pump is nearly new, they replaced the thermostat with a 195 degree from a chevy dealer, the radiator HAS been flushed.

Have not checked for a 'collapsing lower hose ' as mentioned on several other postings...they still have the car.

Am also having problems getting it to pass the new emissions inspection in Texas. High hydrocarbons and carbon monoxide.


One shop suggested they might need to replace the 305 chip with a 350 chip. Any truth to that?????


Any help would be appreciated.

 

There could be numerous reasons for this.

What temp is the fan(s) kicking on at?

what pressure cap is on the radiator?

Did they get all the air out of the system when they reflushed it?

The stock 2 row should be plenty fine for your
350..


-- Joe

 

Replace the radiator cap.

 

to update this...got the car back the dealer pressure checked the system and it was OK, they replaced the stock radiator with a 3 core copper/brass, replaced the Temp control sensor for the temp guage, the Rad cap IS new. And guess what...no more overheating or boil over.


Still won't pass the state of Texas' new emissions test....failed ONE stinking test out of 10. CO was .41 ppm too high....

 

Car is running too lean if the CO's is that high, which is prolly why
you were running hot.

Retard the timing to 0. If its allready 0, retard it -1 or so and try again..


CO's = high timing / too lean
HC's = gas not burning right / too rich


-- Joe

 

The emissions aren't "that high". The allowable is .86 parts per million at 15mph. It measured 1.21 ppm at 15 mph. A cow farting probably puts out more carbon monoxide than that car does. We're sitting at .35 ppm too high. Only issue with setting it and retesting it,and trying again IS that the test costs 38.50 and you get ONE retest on it before you have to pay again. Could get pretty expensive trial and error.....

 

My first 2 guesses were that the timing was advanced too much, or that it was because of the 305 radiator. I swapped from a 305 to 350, and it ran fine, but the temp. would get a little higher than i wanted...it'd run at around 235 instead of the 220 norm...so i swapped in a 3 core brass and it started running at about 195...problem solved. This was w/ me running a single fan setup. As far as the timing, that could still be your problem, but just may not overheat now because the radiator is doing such a good job....so i'd still check the timing....make sure it's not turned over (turned all the way back around to what it's set at)...that's probably ur emissions problem too. And you said something about swapping to a 350 chip? Well when they swapped in the 350 TPI, did they keep the 305 TPI, or did they swap that to a 350 setup also? If they went to a 350 engine/tpi, then yes you need a 350 chip...but if they stayed w/ a 305 TPI setup, then you should be able to run "alright" w/ the 305 chip. I ran 305 tbi w/ a 305 chip for a while on my 350 before i swapped to 350TPI.

 

they kept the 305 TPI setup....what's the best way to check the 'turned all the way around'

 

arent these engines supposed to run well above 200' for proper sniffer results? (like aruond 200 to 220?).
if it still doesent pass and u dont have much scruples or a guilty consience, and a few extra bucks, well i guess u know what u would have to do. ;0)

 

Well yeah, but it's more that the cat needs to be hot more than the block, but yes you are correct - 210 for emmisions.

If they kept the stock 305 TPI setup I'm not sure how long your pistons are gonna lest, especially the front two cyls.. You might wanna pull your plug and check for peppering. 305 injectors
won't run rich enough for the 350..

The 305 - 350 chip I'm not sure about. I tried running both, other than spark curve I didn't see any difference running rich/lean, my .O2 readings were the same. But the 305 injectors are gonna make you run too lean, which could be the problem right there.

Thats the problem with some garages that don't fully research something before they do it, just cuz the bolts lined up doesn't mean its gonna WORK.

-- Joe

 

A little confusion....is the issue the injectors or is the TPI body actually different from 305 to 350? If just the injectors, I would assume purchasing new ones and replacing them would be fairly straight forward?!?!?

Also, what would the powers that be recommend for injectors...remember this IS a daily driver for a 16 year old. Do not want it to break any land speed records.

 

injectors...remember this IS a daily driver for a 16 year old. Do not want it to break any land speed records

i remember when i told my self that three year ago when i got my first f body, a '78 firebird espirit. trust me, those words will desolve quickly when ur 16, 17, 18. ;0)

 

I can say that 'cause I'm the dad that bought the car for the 16 year old....

I can only hope that he will be mature enough to NOT try to race everyone that comes along....besides the FIRST ticket for speeding causes a loss of car for definite period of time....the first contest of speed ticket loses car permanently AND license for period of time...

 

It sounds like you have couple of issues........ Your car still has the stock 305 19lb injectors and the 350 uses 22lb injectors. Also you are using a 305 chip with a 350.

Get 22lb injectors and a 350 chip for the same year (actually I'd use one from an 89 because it will eliminate the need for the cold start injector). Have fun

 

Sounds like dad shoulda bought a honda..

Like recommended, verify that you need the new injectors, and chip.. Most likely you do. That motor won't last long if its running lean..

You could also as an alternative buy a f/p gauge and a adjustable regulator, which would be good in the long run if you were trying to make the car fast; but it appears thats not the goal at hand.

-- Joe

 

"Shoulda bought a honda"

No child of mine is going to drive a rice powered piece of scrap iron ...at least NOT if I am buying it..... :lala:


Maybe when he gets out on his own.....NAH...even he makes fun of his ***** buddies....

 

Most are Alum/steel, but I get your point.

Hope you work out the bugs in the car. Good luck.