4bd1 won’t start when cold

[Obsferd73]

Hey all, I’m now here. Also, I’m from the states.

I have a 1985 all terrain 4x4 forklift with an Isuzu 4bd1.

I have owned it for a few years and I’ve never had any luck getting it to start cold. I have to use starting fluid for a cold start. Blow by is minimal so I’m not convinced it has low compression just yet.

I’m In Florida so it’s usual if warm here. The glow plugs are not hooked up either, but I’ve read these engines don’t usually need them.

Any ideas on what to do? I have read about a banjo fuel filter Steiner, but I’m unsure where that’s located at.

[JDNSW]

The 4BD1 should start without glowplugs in Florida's climate, provided:-

1. Compression is OK, and you say it is. But how do you know? My criterion for "down on compression" is "won't start from cold without glow plugs"!

2. Starter turns it fast enough. This may be the issue,anywhere from starter is sick to bad wiring connections, to solenoid contacts to slipping free wheel in starter drive.

[Obsferd73]

The 4BD1 should start without glowplugs in Florida's climate, provided:-

1. Compression is OK, and you say it is. But how do you know? My criterion for "down on compression" is "won't start from cold without glow plugs"!

2. Starter turns it fast enough. This may be the issue,anywhere from starter is sick to bad wiring connections, to solenoid contacts to slipping free wheel in starter drive.


My assumption compression is good is just that, an assumption. I did just get a diesel compression tester and will 100% be doing a compression test on it when time permits.

On a 4bd1 what compression numbers are acceptable? Based off my knowledge of a 7.3 international I would look for 400psi being a healthy engine and 350ish or lower being more worn/tired.

The starter does appear to turn over quickly / fast enough for a cold start. It is not sluggish. I have replaced the battery cables since owning it.

[tc_s1]

Just a bit North of you with 4bd1's myself and only rarely has there been any challenge; once when very cold and I had to resort to glow plugs, and a few others times when the starter was going bad but not yet audibly demonstrating it. Rebuilt the starter a few years ago and has been good since. Not much help I'm afraid but wanted to weigh in with a little data.

[Obsferd73]

Any insight as to where the banjo filter screen is? I want to ensure it’s not a fuel restriction causing my starting issue.

[JDNSW]

On the bottom of the injector pump if it is the same as mine, but unlikely to cause starting issues in itself.

Not specific to the 4bd1, but for any similar diesel, anything that allows air into the fuel supply system will cause starting issues. This may be indicated by a slight sign of fuel leakage - if air can get in, fuel can probably get out.

[workingonit]

... I have to use starting fluid for a cold start...

Greetings from the warm north to the warm south. My 1984 LRover 4bd1 fires up without glowing, but with good battery and good starter rpm. My understanding is that the Australian Army chose this engine because if could start from cold without a glow procedure.

Regarding cylinder pressure. By comparison the Land Rover Tdi 300 is around the 350-400 psi range which I guess is standard for the physics of fuel oil ignition.

Are you using ether for starting? Often a point of debate, but my understanding is ether should not be used unless specified by the diesel manufacturer, danger of ring damage because it ignites well before top dead centre.

Regardless, it sounds like you have had it running, but without issues? Will it start readily after you have warmed it up? Have you cracked any of the injector lines to see if fuel is flowing freely? I'm assuming your engine is stopped by a push/pull cable, otherwise do you have a faulty electric fuel cut off solenoid or EDIC motor? Oil pressure sensor faulty?

I have, by way of example, a 3 cylinder diesel 6 foot deck mower where the previous owner replaced the original mechanical lift pump with an electric Facet pump. Without this pump running the injector can't pull fuel. Any home made remedies like this on your machine?

Have your tried connecting the current to the glow plugs? Not that you should need to with the 4bd1.

Keep in mind, if its a basic circuit, the battery current should first go through a dash mounted resistor that heats up to an orange colour. The resistor lowers the amps before hitting the glow plugs ie don't connect your battery directly to the glow plugs.

Not sure this is a concern for the 4bd1, but some diesel glow plug starter circuits have cold weather current boost activated by a temperature sensor under the bonnet, along with a timer designed to start the glow procedure just before ignition and keep it on for a moment after the engine has started.

[Bearman]

[QUOTE=Obsferd73;3190237]My assumption compression is good is just that, an assumption. I did just get a diesel compression tester and will 100% be doing a compression test on it when time permits.

On a 4bd1 what compression numbers are acceptable?


440psi is the top figure to look for.