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Author Topic: New guy... 81 Rabbit diesel. Won't start...  (Read 794 times)

October 30, 2016, 09:58:02 pm

Lizard 1

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New guy... 81 Rabbit diesel. Won't start...
« on: October 30, 2016, 09:58:02 pm »
New guy here and did a search, but nothing similar to what we have going on here.  Purchased an 81 Rabbit 1.6 and having starting issues.

Previous owner indicated that there was an issue getting ti started and had to "persuade" it to start.  When we do get it started, it runs like a champ and runs for whatever time we have drove it. 

After the day we bought it and sitting over night, we cannot get her fired.  We replaced the fuel filter (filled it up and checked the old filter for any oil, etc.), put in some Stanadyne and cannot get her started.  Just turns over and over and drains the battery.

Why would this car start sometimes and run great when it does fire but others, just will not fire?

New to these small diesels and used to Ford diesels only. 

I am going to try and get a manual tomorrow, but felt like maybe this might be something others have seen and can direct me where to look.  I replaced the fuel filter y filling up to the top and putting back on.  Was told we didn't need to prime the system if we did that.  Not sure if that is accurate or not...

Any help for us as this is a project for my son and I...



Reply #1October 31, 2016, 12:36:53 am

ORCoaster

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #1 on: October 31, 2016, 12:36:53 am »
Do a search for Glow plugs, Air in Injection Pump and Hard to start.  I bet you will find a ton of like threads. 
Now Own 1981 Caddy as the NEW DISTRACTION to all that is around me.  Project Away!

Reply #2October 31, 2016, 09:31:38 am

Lizard 1

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #2 on: October 31, 2016, 09:31:38 am »
I did...  However, the issue is that I don't know where to start.  I don't want to go replacing the pump, glo plugs, injectors, etc if I can start somewhere first and work that direction.  I would think the pump is ok or it wouldn't run great when it does fire up.  I would think the same with the injectors.

I am wondering if the glow plugs are an issue, but hate to replace all four as I read some people saying it is potentially one, etc.

We do have an airbox that has broken tabs at the bottom and not making a solid seal.  I did fill the filter to the brim, but there could possibly be air in the system... 

I am just trying to see if someone reads the same situation and can comment because they had the same issue.  I will check more in depth on the hard start topic and see what else I can discover.  It's just a ton of scanning to only find it doesn't apply.. Hence the topic start.


Reply #3October 31, 2016, 10:33:29 am

TylerDurden

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #3 on: October 31, 2016, 10:33:29 am »
Starting poorly, but runs fine.... so many discussions that you're gonna get a drink with a fire hose.

Best way to prime, is suck fuel all the way through the IP by putting vacuum on the line coming out of the IP. Don't wait to try after priming, or the fuel can draw back toward the tank and pull air back into the IP from the return line.

I'd check:
Air in lines (use clear fuel line)
Glow plugs (each should draw ~12A, use bosch duraterms)
Compression (>300psi)
Starter speed (needs to be fast, esp w low compression)
Timing

Reply #4October 31, 2016, 10:57:31 am

vanbcguy

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #4 on: October 31, 2016, 10:57:31 am »
Glow plugs are easy to test without removing.

Step 1: with the engine cold turn the key on. Does the glow plug light come on? How long does it stay on for? If not your relay is likely bad (it has the control circuit built in)

Step 2: cycle the key and immediately check for 12V at the glow plugs (metal bus bar along the front of the engine below the injectors). If no power there when the GP light is on then check the big 50A fuse on the firewall. If no power there then you're back to the relay.

Step 3: if you have voltage at the bus bar and a cold engine you should be able to simply touch the terminal on the glow plugs with your finger. If you have cycled the key a couple of times they should all feel warm to the touch. Any that are cold need to be replaced. Bosch Duraterms are the best way to go.

Sent from my XT1097 using Tapatalk

Bryn

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Reply #5November 03, 2016, 07:46:31 pm

Lizard 1

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #5 on: November 03, 2016, 07:46:31 pm »
So, we pulled each glow plug and ground on metal and turned the key on.  Each plug got red hot.  Cleaned the ends, cleaned the copper strip and replaced.

We replaced the fuel filter also.

Also got a new battery.

The car turns over but starts to drag a tad after a long period - which is expected...

The dash lights come on and go out. 

We did FINALLY get it to start.  We held the throttle wide open and turned it over.  Gained speed in terms of sounding like it was firing.  Then she FINALLY kicked on.  Purred like a kitten.  Idled fine and had good power.  Ran her about 20 minutes and took it on the freeway and got to interstate speeds.  Shifted great and ran smooth.  Downshifts were nice and when at stoplights, idle speed was perfect.

Stopped at the gas station to get some air and my son wanted to drive back.  Fine enough...  However, he stalled it on take off.  No worries...  Should fire as it has been running a good while.

Never fired.  We couldn't replicate that firing sequence we did before.  Oil level is fine.  Just turned over and over and over and over... 

I am asking these questions:

1) Could it be the starter?  Even though seems to turn over fine, I don't have another rabbit to compare against. 
2) If it were the pump, wouldn't the car run poorly or at least when at idle or load? 
3) Same question as #2 but for the injectors - wouldn't the car have some sort of hiccup or surge, sputtering, etc?
4) Compression?  Could the motor be tired?  Again, wouldn't it struggle to run nicely and briskly (for these diesels) to highway speeds over 70?

It's baffling.  Anyone know a solid older diesel tech in Columbus, OH?

Reply #6November 03, 2016, 08:55:18 pm

air-cooled or diesel

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #6 on: November 03, 2016, 08:55:18 pm »
sounds like an injection problem, either that or a timing problem, could be a compression problem. or air in inlet line, to inj pump.
1wire will do it all-
0-60.must still be in school.

Reply #7November 04, 2016, 08:18:25 am

TylerDurden

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #7 on: November 04, 2016, 08:18:25 am »
Quote
1) Could it be the starter?  Even though seems to turn over fine, I don't have another rabbit to compare against. 
2) If it were the pump, wouldn't the car run poorly or at least when at idle or load? 
3) Same question as #2 but for the injectors - wouldn't the car have some sort of hiccup or surge, sputtering, etc?
4) Compression?  Could the motor be tired?  Again, wouldn't it struggle to run nicely and briskly (for these diesels) to highway speeds over 70?

1) not likely in this case
2) the IP could have a bad cutoff valve (or intermit 12V), sticking internal parts
3) not likely in this case
4) more likely in this case... they can run well, once started


I'd check the big 3: Fuel, compression, timing.

Fuel:
When it won't start/run, loosen the lines at the injectors and verify fuel when cranking... if none, ensure 12V at cutoff valve and get clear lines to/from IP to verify fuel at the IP with no air infilration.

Compression:
A tester, of course... but if she cranks very fast, or if a block heater helps, then compression might be low. Once running, a low compression engine can seem fine, but can be stubborn to start.

Timing:
Check with book and gauge, but a clue to mis-timing is grey smoke (too retarded) or excessive nailing (too advanced). Not likely in this case, so far.



Reply #8November 04, 2016, 08:51:50 am

air-cooled or diesel

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #8 on: November 04, 2016, 08:51:50 am »
2) the IP could have a bad cutoff valve (or intermit 12V)

Fuel:
... if none, ensure 12V at cutoff valve and
does inj pump solenoid 'click' when it has power??
have wifey cycle key, listen for solenoid to 'click' although this doesnt seem to be the problem,,
i vote next to trace down---air in inlet line to inj pump(should be a clear/semi-clear line coming off fuel filter).
1wire will do it all-
0-60.must still be in school.

Reply #9November 04, 2016, 09:35:00 am

TylerDurden

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #9 on: November 04, 2016, 09:35:00 am »
A "click" is not proof-positive.  ::)

12V needs to be steady at the terminal.

The valve plunger can also be faulty. It is simple to remove the plunger and run the engine, shutting-off will require mechanically stalling or suffocation.

Reply #10November 04, 2016, 03:15:40 pm

Lizard 1

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Re: New guy... 81 Rabbit diesel. Won't start...
« Reply #10 on: November 04, 2016, 03:15:40 pm »
Was going to use clear hosing on the pump to filter.  Anyone know what is best to use?  Also between the injectors as one has already been replaced and very soft.

I assume the original dia from the pump is about 1/4"?  How big between injectors?  Just want a tight fit and measuring the ones on there are stretched...

 

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