Hard starting when hot

[Cold Chuck]

Alright, esteemed folks.

 

Recall my earlier thread about swapping AT transmission etc.. I decided to start new thread.

 

After reassembling 5MT D/R transmission with new synchronizer ring (60.00 from Fred Bean Subaru) and stabbed whole thing into 1987 wagon . It shifts fine. Previous fuel mileage was 20 MPG (hand calculated) and now its 23 MPG. I replaced all 4 seals in the tranny before reassembling. I used Royal Purple 80-90W oil with 1 quart of engine Reslione. When the engine is hot and shut down for 10 or so minutes, it will not restart until cranking with throttle all the way down to the floor for 7 seconds or so. So this weekend, I grabbed another Hitachi carb - this one has high altitude modifications already on it. Swapped it into this car. I haven't driven it long enough to calculate the fuel consumption but I went to the store to get some stuff rather than drive my Cummins. After coming out of the store and getting into the car, it still wont start after cranking. It will start if I hold down the pedal all the way to floor and crank for 5-7 sec. It was like this before I pulled the automatic transmission with bad governor gear and after putting into 5 speed manual and after swapping carb from sea level carb to H.A. modified carb from donor car.

 

When it is cold - it ALWAYS starts easy. Just very hard to start when HOT. I checked the choke and its fully open but wont start.

 

I am thinking - timing (its set at 9-10 degrees) or bad ingition coil? Can I use ACCEL yellow coil? Or forget about whole thing and go to junk yard and locate SPFI car? I dumped few cans of Seafoam in tanks few times at fillups before I swapped the carb with no luck. On my next fill up I'll put in1 more can of seafoam in it for the "new" carb.

 

By the way, this is directed to G.D. & Turbone when I swapped the tranny, I did not have to replace those two radius plates to install the transmission cross member. Just FYI. I havent finished with reverse lights and cruise control issues with clutch. Oh by the way, I bought entire FSM books for 1987 Subaru (all 6 sections) off fleabay for 29.00.

 

Thanks!

[GeneralDisorder]

Have you tested your compression? I think you may have low compression and thus it want's the choke on even when warm/hot. IE - not enough vacuum at low RPM to get the fuel in with the choke plates open.

 

Have you thought about installing a manual choke kit? They are about $8 at my local parts store.

 

It's a thought anyway.

 

Glad to hear you didn't have to swap the radius plates.

 

GD

[audio_file]

check for vacuum leaks at the carb too (the ol' carb cleaner mist/spray test) my carbed wagon had a very similar issue and it turned out i had a out-of-view and unplugged vacuum hose at the carb causing the issue

 

chris

[misledxcracker]

See, I was right about swappin them plates But watch me ending up having to..

 

+1 on the vacuum leak issue.... I replace ALL of the vacuum lines under the hood of any car I acquire. Can, and most likely will save a headache or two, maybe more.

[McDave]

It sounds like you're getting vapor lock. Check your fuel lines and hoses routing to make sure they are not near anything that gets hot, like the exhaust or heater/radiator hoses.

[Cold Chuck]

1) - I will do compression test later this weekend. This car/engine is 72,000 miles on it. Transmission and high altitude carb came from donor car that has 165,000 or so miles. Does not smoke (unlike my Cummins BBCOD with 50 HP stage 1 injectors). I will find and install vacuum guage and report the readings over the time.

 

2) - I did carb cleaner spray all the way around the car, intake manifold and all the hoses - no speed increase or stumble - that was done on original carb and on the new high altitude carb. Then I tried ether (starting fluid) with no results either. I'll replace the hoses next time I pull the air filter housing. But I would like to know what is the problem before I throw parts at it.

 

3) I was thinking of vapor lock but in my experience with jeeps with mechanical fuel pump, we have problem with it especially up here in the rockies which I ended up covering fuel lines with heat shield foil material. That helped. On this car, it has electric pump (may be low psi) and has factory fuel lines routing that is away from the exhaust area. The fuel lines are on the left side of engine bay under the master cylinder leading directly to the carb and to the black charcoal canister on the right side of engine. Diagnosing vapor lock is harder than diagnosing other problems because its dependent on the amount of time of heat soak and gas quality, etc... in my opinion. I'm just a retired diesel mechanic by trade. :-\

 

Thanks for the advices, folks. I'll keep you posted.

[brokebill]

same problem(word for word, even where my timing is set) with my carbed 86, thought it was choke related but not so sure now.

 

if anyone knows i would also like to find out about what coil i can use.(mine has the nippo. distributor)

 

parts places have a lot of misinformation on our cars and sick of getting wrong parts.

 

sorry to post on your thread but a common goal.

 

thanks and please update on your car as you search/eliminate/repair

 

Bill

[GeneralDisorder]

"Vapor lock" happens (as the name sugests) when fuel lines going TO the fuel pump overheat. This vaporizes the fuel and the pump can't operate (liquid fuel pumps don't pump fuel vapor).

 

This CANNOT happen on a Subaru. Period. The pumps are electric (IE - not mounted on the engine), and the are under the car by the fuel tank. Vapor lock is a literal impossiblity on a Subaru. The pump will ALWAYS have liquid in it and even if a line ahead of the pump in the engine bay should have some vapor in it, the pump will push it out regardless because the pump is primed with cold liquid fuel from the tank.

 

Vapor lock is a thing of the (distant) past. It went the way of the dodo when mechanical fuel pumps did.

 

GD

[McDave]

"Vapor lock" happens (as the name sugests) when fuel lines going TO the fuel pump overheat. This vaporizes the fuel and the pump can't operate (liquid fuel pumps don't pump fuel vapor).

 

This CANNOT happen on a Subaru. Period. The pumps are electric (IE - not mounted on the engine), and the are under the car by the fuel tank. Vapor lock is a literal impossiblity on a Subaru. The pump will ALWAYS have liquid in it and even if a line ahead of the pump in the engine bay should have some vapor in it, the pump will push it out regardless because the pump is primed with cold liquid fuel from the tank.

 

Vapor lock is a thing of the (distant) past. It went the way of the dodo when mechanical fuel pumps did.

 

GD

 

Yeah, I didn't realize carbureted Subarus had electric pumps when I wrote that. My mistake.

 

Cold Chuck, have you tried looking down the carb throat for gas boiling over after a hot shutoff? Float level good? Two bad carbs (not likely)? Too much fuel pressure?

 

Reminds me of the time an older Chevy Monte Carlo came in flooding. A coworker held the pressure gauge on the mechanical fuel pump while I cranked it over. He said look at this! It read 6 lbs? He said no, the needle spun all the way around once and stopped at 6 lbs! New pump fixed that one.

[erez]

I write to you what are thr reasons ' I have the haynes manual of the car

1.air fillter clogged

2.fuel not reaching the carburetor or fuel injection system

3.corroded batarrey connections ' especially ground.

4. faulty coolant temperature sensor or intake air temperatue sensor

5. carburator or choke problem

 

good luck:)