starts fine, smooth idle 30secs, rough idle, then dies

1990 I would have assumed carburetor, but if it is TBI, that does change things some. Please let us know what setup you have, as it will help us figure it out.

Isn't this TBI? If so then I guess fuel pump relay or oil pressure switch.

When I turn the ignition key on, it just "clicks". When I turn it a second time, the engine starts and runs for about 15 sec., the engine light comes on and it quits running. It will restart again, but the same problem comes up.

Generally speaking, engine surge at idle usually means it is running lean. Quick way to confirm it is running out of fuel would be to keep a can of starting fluid handy (or WD40, which works just as well). When it starts to die, squirt some down the carb. If it keeps running on starting fluid, then you are running out of fuel - for whatever reason. Your fuel pump may be dieing. If it is, I would scrap the mechanical pump and install an electric pump. The reason is that since most RVs sit for extended lengths of time, its nice to be able to kick the pump on and let it prime, when it has been sitting for a few months. Also, depending on where you mount the pump, it will prevent vapor lock. One other thing, since the mechanical pump has a return line, replace the mechanical pump with an inline fuel filter that has a return line as part of the filter. This will help regulate the fuel pressure, as those electric pumps tend to run a tiny bit high.

I had a '90 GM car, did the same thing, replaced filters, etc., nothing changed, then discovered it was the coil pack in the top of the distributor. Easy to replace and I never had another problem.

But, your issue does lean towards a bad fuel filter. Your clogged filter will slowly let the bowl fill, after you start the MH, the bowl empties faster than fuel can seep back into the carb bowl, and you run out of fuel.
An easy way to diagnosis a fuel problem is:
Start, run until it dies,
then disconnect the fuel line from the carb, place a quart size plastic bag over the line an secure tightly with a rubber band,
remove the wire from the coil (you don't want to start the MH)
Crank and watch the fuel flow into the bag. If you get a lot of good squirts filling the bag in just a few seconds, then fuel flow is OK, look elsewhere for the problem. If fuel to the bag is very minimal, then you have a clog somewhere in the fuel line or filter.

Sounds like fuel delivery to me too...it starts, uses up its supply of fuel, then starts to run out of gas....when its fuel supply is gone, it dies...replace the fuel filter, not clean it. Also are you sure there's only ONE...?....Dennis

april10 wrote:
We have a 1990 Southwind motorhome. Ran fine until recently. Now, it starts right up, runs good for about 30 sec., then the idle gets rough, the motor sounds like it's surging, and it dies. My husband cleaned out the fuel filter (there's only one) but its not the problem. Any suggestions would be greatly appreciated! Thanks!.

Need to replace the fuel filter not clean it. Did he replace the air filter? He may have two fuel filters, one on the chassis rail and another on the carb/EFI fuel inlet.

I am guessing fuel filter.. but that is a guess.

Depending on the fuel pump location (Tank or engine) it might be a religious fuel line as well (It got holy) and letting air into the system reducing pump effiency. This is not possible with a tank mounted pump.

Yeah, sounds like fuel delivery and specifically after the cold start period. If you give it gas to put it above idle, will it still die after those 30 second? Also, if it has died and you start it again, will it run for a while and die again or does it not run at all?

The EGR is usually activated at cruising speeds and shouldn't affect idle speed but you can remove the vacuum line to it to see if that stops the problem.

D.E.Bishop wrote:
april10, We had a similar problem with our Bounder, it was the spark plug wires. OEM wires lasted a long time while the replacement set died quickly. Replaced twice under the shops warranty. Cost of wires was about 150 bucks.

I can't imagine how bad plug wires would allow it to start and run fine for a short time then quit. It sure sounds much more like a fuel problem though its possible that if it has the electronic ignition that it is failing but I will still say most likely it fuel related.

Question : when it quits, how long before it will start again?