1988 Rolla Cs Ae82 4ac Carbi Problems

[MaxRolla88]

Hey all, I'm a bit new here, I've introduced myself on the syd forum, but for the rest, My name's Mon.

I have recently acquired an old 88 ae82 4ac carbi rolla off my mate Brady. It used to run fine but in the last few weeks it developed idle and battery charge problems.

With the idle it would idle at (I'm guessing as it has no tacho) about 1k with no problems. After a while if I took my foot off the accelerator it would simply just stall [the car is an auto].

As for the battery charge, car would stall and then die, as in not turn over at all as I'm assuming the alternator was not charging battery. Charge light would always be on, except for when in 1st gear at high revs. Was the worst at night due to lights being on. The car died twice on the pacific highway while trying to get it home :)

 

Here's what I've done so far:

- Had battery tested, bettery is fine (although it is an NRMA replacement battery. a new one is planned)

- removed head unit to see if that was taking some of the charge. Pretty sure it was

- replaced alternator with almost new alternator (it had only been cranked once apparently). This fixed my charge problems.

 

Here's what myself and my mate are planning to do:

- clean out the carbi

- replace oil

- juice up the idle

- install a new battery that can power my engine and head unit.

 

Am I on the right track or could there be a bigger problem here?

Any opinions or suggestions would be greatly appreciated.

 

Thankyou

Edited May 13, 2009 by MaxRolla88

[MaxRolla88]

Anyone have any ideas?

[mikey_m]

Anyone have any ideas?

 

You might need to reco your carb, I had a similar problem on my old one, when we blocked all air flow it would rev up on the bypass OK, but would not progress when open naturally. Basically there was gunk and crap all built up. Picked up a cheaper re-built carb from the local mechanic and viola it was all going again.

 

Anyone else with thoughts?

[skippy1331]

hi yeha i live in south east suburbs of melbourne. i own same car but in manual. i have same problem. the car runs fine, but when this problem occurs the revs usually sit around 1,100 rpm but it sits around 4-500 rpm, and in alot of the time will just totally drop off. and engine cut out occurs. my old man and i replaced both the fuel filter and spark plugs. this fixxed it for a while then a week later i was driving around and then stopped at traffic lights and the cars does the drop to bellow 500 rpm. i was like SHITE@ need to get home our else will become pain in the bumm. got it home and then turned it off and turned it on again and the engine just cuts out. so i left it for 1hr and came back and the same thing happens engine cutt out. so i restart 3 times and it decides to sitt at 1000 rpm, so i just reved it in incriments of 500 rpm too 3000 rpm and then drop it down in those incriments and it didnt drop out, so i went for a 30km drive and was all good. i have noidea what the problem is. hopefully its sommething easy. I'm thinking its the auto choke. not responding to keep the motor at proper idle. but could be dodgey fuel.. just yea I'm only 19 so i have noidea. if it turns to shit ill just get RACV to come figure it out!

[clubby2084]

Yep, bloody carbs on the 4AC' will do this to you. Mine sent me right round the twist (and still does). 4AC motors are know for being a bit weak in the vacuum department.

So anything vacuum operated (like the carb) will suffer if it's not getting the right amount of vacuum, due to a leak or blockage.

 

A simple fix I recommend, ditch the 4A and install something EFI, 4AFE or 4AGE. I got talked out of this option and regret it.

OK, OK, THE most simple fix is a tin of carby/throttle body cleaner. Use the whole tin, inside and outside the carby. Drown the sucker in it...

 

Check all vacuum lines. Any perished, cracked or holed lines will cause no end of vacuum problems.

There are also a number of one way valves on these vacuum lines. Check the are doing the one way thing (and the right way round) and not blocked or free flowing.

There is a schematic under the bonnet that clearly shows were the vacuum lines go. Follow it and you shouldn't have any problems (get the workshop manual if the schematic is gone).

 

There is also a idle up valve at the back of the carb (vacuum operated, of course). It's job is to stabilize the engine idle under load, such as turning on your Air Conditioner.

If it is gunked up the engine idle can be all over the place. One minute OK, next, too high, then too low. This one I let a mechanic fix.

 

That was the problem with mine. It would idle at 1500rpm one minute, stall the next. If I used my Air Conditioner it would drag the idle from 1500rpm to 750rpm (I live in Darwin so I use the A/C almost 24/7). But the erratic idle was causing problems with the A/C. I had the idle valve cleaned out (it was just gunked up but they do perish with age) and problem solved. A/C on or off it now idles perfect at 800rpm.

 

Good luck, start with the lines and valves first, then if that doesn't work pay someone to do it. You might get lucky.

[skippy1331]

Yep, bloody carbs on the 4AC' will do this to you. Mine sent me right round the twist (and still does). 4AC motors are know for being a bit weak in the vacuum department.

So anything vacuum operated (like the carb) will suffer if it's not getting the right amount of vacuum, due to a leak or blockage.

 

A simple fix I recommend, ditch the 4A and install something EFI, 4AFE or 4AGE. I got talked out of this option and regret it.

OK, OK, THE most simple fix is a tin of carby/throttle body cleaner. Use the whole tin, inside and outside the carby. Drown the sucker in it...

 

Check all vacuum lines. Any perished, cracked or holed lines will cause no end of vacuum problems.

There are also a number of one way valves on these vacuum lines. Check the are doing the one way thing (and the right way round) and not blocked or free flowing.

There is a schematic under the bonnet that clearly shows were the vacuum lines go. Follow it and you shouldn't have any problems (get the workshop manual if the schematic is gone).

 

There is also a idle up valve at the back of the carb (vacuum operated, of course). It's job is to stabilize the engine idle under load, such as turning on your Air Conditioner.

If it is gunked up the engine idle can be all over the place. One minute OK, next, too high, then too low. This one I let a mechanic fix.

 

That was the problem with mine. It would idle at 1500rpm one minute, stall the next. If I used my Air Conditioner it would drag the idle from 1500rpm to 750rpm (I live in Darwin so I use the A/C almost 24/7). But the erratic idle was causing problems with the A/C. I had the idle valve cleaned out (it was just gunked up but they do perish with age) and problem solved. A/C on or off it now idles perfect at 800rpm.

 

Good luck, start with the lines and valves first, then if that doesn't work pay someone to do it. You might get lucky.

 

 

this all sounds exactly the same as mine thanks heaps. except i know little to nothing about cars. so whats "A simple fix I recommend, ditch the 4A and install something EFI, 4AFE or 4AGE." i have noidea what that is. but yeah from the sounds ill just take it to a mechanic and let them sort it out. as i don't what to touch anything cos i don't know what it is or how it works...

[clubby2084]

this all sounds exactly the same as mine thanks heaps. except i know little to nothing about cars. so whats "A simple fix I recommend, ditch the 4A and install something EFI, 4AFE or 4AGE." i have noidea what that is. but yeah from the sounds ill just take it to a mechanic and let them sort it out. as i don't what to touch anything cos i don't know what it is or how it works...

 

The 4AC motor runs a carburetor as a means of supplying the fuel and air into the engine, hence the "C" in 4AC. I have a personal dislike of carburetors. I've never had one work properly in 20 odd years.

A 4AFE or 4AGE are both Electronic Injection. More reliable and economical, and more power. It's a win win. The down side is the initial cost of installing an EFI engine.

It all depends on what you want with from the car. If it's just transport pay a few hundred dollars and have the carby repaired. If you want more power and have plans to do the car up, and maybe keep it for a few years. Go for the 4AGE.

 

Have a good look around this site. You will get some great ideas.