Hard Starting 1HZ

Submitted: Tuesday, Jan 04, 2005 at 15:30
ThreadID: 19064 Views:20801 Replies:8 FollowUps:13
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Can anyone suggest why my 1HZ ('99 75 series) is hard to start. It starts fine first thing in the morning, but anytime after that it takes about 3 goes to get it going.

I've replaced the glow plugs, there is power to the fuel cut solenoid, I've also replaced the coolant temperature sensor.

I have dual batteries, the starter motor operates off both batteries. The main battery is on it's way out now, and have noticed that the starting has gotten more difficult since (but still starts fine in the morning, albeit slower cranking).

It appears to be a temperature related problem (ie. when motor is hot - difficult to start). Could it be that the wiring to the glow plugs is buggered, therefore when the motor is hot, it increases resistance through the circuit????? I don't know, just grasping at straws now..... any help would be greatly appreciated.
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Reply By: tour boy - Tuesday, Jan 04, 2005 at 15:35

Tuesday, Jan 04, 2005 at 15:35
Clean ALL earth leads and power leads in the engine bay. But disconect the batteries before doing the terminals on the starter motor. Make sure the battery leads are immaculate. Will solve this problem in 99% of cases.
Tour Boy
AnswerID: 91288

Reply By: Member - Davoe (WA) - Tuesday, Jan 04, 2005 at 15:45

Tuesday, Jan 04, 2005 at 15:45
These are pretty basic babys - forget the heat thing a hot motor will always start easier you dont actually need glow plugs to start them it just makes it easier and on a warm day you wouldnt know they werent working (I have a manual glow plug activator) replace your dud battery it will suck charge from your other battery giving you 2 dud batterys duel battery systems are only as good as their worst battey. That leaves the 2 basic needs fuel and air. Give it a good blast flat in 1st it should run up to 4500rpm and not break down if it doesnt then check filters the last fuel related problem I had was a blocked primary. Get your mate to give it a whirl while you watch does it blow thick black smoke (some under power is ok) or white smoke (starving) if fuel filters are ok that leaves the fuel pump/cut off solonoid which needs specialist attention. Also check your prime pump making sure it is firm and not spongy idicating air in the system. Garanteed it will be fuel related somewhere
AnswerID: 91289

Follow Up By: Member - Davoe (WA) - Tuesday, Jan 04, 2005 at 15:49

Tuesday, Jan 04, 2005 at 15:49
oh hang on do you mean turns over well but doesnt start or is difficult to turn over if it is difficult to turn over check your charging at 14v and if so turf your battery they are a very disposeable item in 4bys
FollowupID: 349838

Reply By: Oznuggets - Tuesday, Jan 04, 2005 at 19:14

Tuesday, Jan 04, 2005 at 19:14
Scott, do you mean it isn't cranking well when warm or just not firing? I have a small problem with my 1hz that when I leave it for about a week without starting it takes alot of coughing and spluttering before it gets going. Last time I changed the fuel filters I noticed that the fuel lines were quite loose and easy to pull off even with the clips on them. I suspect that mine is getting air into the system when left for more than a few days as otherwise it's no problem. How many Km's have you on the 1hz? I have seen alot of diesel problems caused by bad fuel and filter systems. good luck, Peter
AnswerID: 91309

Follow Up By: Member - Davoe (WA) - Tuesday, Jan 04, 2005 at 19:23

Tuesday, Jan 04, 2005 at 19:23
funny you should say that just jumped into my work ute after 11 days and no dice. Manuel fuel pump felt a bit doughy so I gave that a bit of pumping then turned it over pumping the throttle finally started to alot of coughing and spluttering. Dont have the same problem with my 2h powered camper even after 3 weeks it starts ok
FollowupID: 349867

Reply By: Member - 'Lucy' - Tuesday, Jan 04, 2005 at 20:11

Tuesday, Jan 04, 2005 at 20:11

I have a 97 1HZ after market turbo'd.

No trouble at all, other than if left standing for over a week I find I have to wait for at least 10-15 seconds after the 'glow plug' light goes out before I give it a kick in the guts. Will fire up straight away.

After that it is straight turn key from off position to ignition/crank - no stop/pause - and it fires up immediately.

Agree with all of above. i.e. (1) dirty power terminals, especially on battery leads. They get a very thin film of S H I T built up between them and the battery post which is one of the best naturally occurring insulators your ever going to get.

(2) Fuel:- Blockage of some sort or air getting in.
AnswerID: 91319

Reply By: Peter 2 - Tuesday, Jan 04, 2005 at 20:39

Tuesday, Jan 04, 2005 at 20:39
I know of tow friends that have had the same sympton with 1hz's at relatively low k's (<200k). Starts fine when cold but hard to start when hot. It would be ok if started 5-10 mins after turning it off but if left for 1/2 an hour or more, no go.
After a lot of stuffing around, batteries, glowplugs, fuel, air filter, it was found to be a worn injector pump, the cure was replacement of the injector pump, not a cheap exercise.
The cause was apparently running on one tank until the engine started to cough and then changing tanks, the injection pump needs a good supply of fuel to cool and lubricate, even the 15 -20 secs before the fuel sucked through done often enough was enough to cause premature wear of the pump.
AnswerID: 91326

Follow Up By: Member- Peter & Mrs Peter, Lez - Tuesday, Jan 04, 2005 at 20:46

Tuesday, Jan 04, 2005 at 20:46
Probably not the best idea anyway, waiting until your engine coughs and splutters before you change over tanks. Liable to suck up water and sediment in the bottom of your tank. I always change over when I get down to a quarter tank of fuel.
Cheers Peter
FollowupID: 349880

Follow Up By: Member - Davoe (WA) - Wednesday, Jan 05, 2005 at 12:17

Wednesday, Jan 05, 2005 at 12:17
very usefull info. I have gone from a 2h wich has an oil lubricated pump to a 1hz with the fuel as lubrication and I hadnt thought of that
FollowupID: 349973

Reply By: dano01 - Tuesday, Jan 04, 2005 at 21:17

Tuesday, Jan 04, 2005 at 21:17
I had a similar problem with my nissan. Yes i know it's a nissan and bla bla bla but this may help you with ideas. I had people tellig me alsorts from replacing the injector pump to performance chips and every thing in between. It could be the end plug in the injector pump this was the cause in mine and got increasingly hard to start when hot to the point where i had to pour about 5l of water on yhe pump the cool it enough to start. See this end plug has some ribs on it to holds presure. when pitted and wore and the fuel thins when hot and the plug wont hold the presure when the engine is stopped. Try the water it wont harm the pump and might give you the solution to your problem. The end plug replacement on my 4wd cost me $42 dollers including fitting so its a cheap thing to fix, but most guys want to charge you the big money of course.hope this helps you.
AnswerID: 91332

Follow Up By: GOB & denny vic member - Wednesday, Jan 05, 2005 at 16:29

Wednesday, Jan 05, 2005 at 16:29
bugger dano
i was just going to tellscott to put a nissan badge on it would fix all problems
FollowupID: 350011

Follow Up By: dano01 - Wednesday, Jan 05, 2005 at 22:16

Wednesday, Jan 05, 2005 at 22:16
Yes i agree putting a Nissan badge on it would fix the problem. you know we nissan people just have to help out the toyota guys now and again with their low tech poor quality vehicles. you know how it is with those guys, it makes them feel better if they think toyotas are better but we know different.
FollowupID: 350073

Reply By: fatz - Wednesday, Jan 05, 2005 at 09:06

Wednesday, Jan 05, 2005 at 09:06
Scott, just a suggestion, have you checked your oil level? these things have a low oil sensor that wont allow them to start if the oil is too low or the oil pressure is not up. When its cold it may have enough oil in the sump but when its warm the oil may be sitting all round the internals. I think the sensor for the oil level is on the passangers side of the sump about 50mm below where it bolts to the block. Check the connections here and the state of the wireing.
AnswerID: 91388

Follow Up By: Member - Davoe (WA) - Wednesday, Jan 05, 2005 at 10:31

Wednesday, Jan 05, 2005 at 10:31
sure bout that? the 2h motor had a no oil pressure cut off but that was to protect them from destrying themselves if the motor started backwards (I had this happen once) I am sure the 1hz does not have it as it cant run backwards. As for the low oil level that is a warning light only and they will happily run with the sensor lead ripped off
FollowupID: 349957

Follow Up By: fatz - Wednesday, Jan 05, 2005 at 10:58

Wednesday, Jan 05, 2005 at 10:58
Davoe, the workshop manual for my 99 HZJ 105, with 1HZ motor tells me that it wont start if it does not have oil pressure. This may be the case for scott, or it may not. It was just a suggestion. The 80 series that I owned with 1HZ motor did not have this feature. Just a humble suggestion based on facts that I have in front of me.
FollowupID: 349962

Follow Up By: Member - Davoe (WA) - Wednesday, Jan 05, 2005 at 11:25

Wednesday, Jan 05, 2005 at 11:25
sorry not bagging you and I learnt something about later model 1hz however if the low oil pressure cut off works like the one on the 2h motors then it must let the motor run for around 10sec before shutting it down because no motor has oil pressure on startup
FollowupID: 349966

Follow Up By: greybeard - Wednesday, Jan 05, 2005 at 11:47

Wednesday, Jan 05, 2005 at 11:47
I used to have a 2h troopie. When I had problems with dead glow plugs ( and lack of compression, just before it died ) it was quite possible to have oil pressure just by cranking the motor without it actually running. I think you will find that it is the same in any motor, the oil pressure pump is a mechanical device, unless you have some exotic racing beast, that operates by the motor turning over by whatever means. Yes the oil pressure will be low until the motor has turned over a finite amount of time but if there is sufficient oil to prime the oil pump then as soon as you start to rotate the crankshaft oil pressure will start to increase, after a couple of revolutions on a 'good' motor the pressure will have reached a sufficent level to prevent the 'no oil cutoff' switch from operating. I also believe that it is inhibited whilst the starter is operating.
The lack of oil pressure will not prevent the motor from starting, it may prevent it from continuing to run which is a different issue.

with regard to hard starting when cold, if the glow plugs are ok, then remove the cables and fittings for the glow plugs and clean every joint/mating surface. Also make sure that there is actually volts getting to the glow plugs. I don't know about the 1hz but it is quite possible to install the links/bars for the glow plug battery feed in such a way that there is no electrical connection on a 2h. Ask the Tojo mechanics who did it to my troopie :-)
FollowupID: 349967

Follow Up By: Member - Davoe (WA) - Wednesday, Jan 05, 2005 at 11:56

Wednesday, Jan 05, 2005 at 11:56
Grey beard, I didnt quite get what you meant by no electrical conectionto the glow plug bars. Is this the same as a manuel glow plug button, I had one installed after my glow plug activator relays or whatever died coz it was cheaper. As for the starter building up oil pressure you are right. On cold mornings I found if i started the vehicle without waiting for the glow plugs to warm up (when the system was still working properly) so it turned over quite a bit before starting I was often able to avoid the double start caused by the low oil pressure cutout activating before pressure was built up
FollowupID: 349969

Follow Up By: greybeard - Wednesday, Jan 05, 2005 at 12:07

Wednesday, Jan 05, 2005 at 12:07
on my 2h there is a metal bar/strip connecting the glow plugs. this had a couple of other small metal strips ( about 10mm wide and 1-2mm thick ) which went from the strip connecting the glow plugs to a couple of insulated posts on the intake manifold. part of which is the current sensor to detect current flow to the glow plugs. At the end( start actually ) of all of this was the cable of to the glow plug relay. the electrical connection is via those strips and it relies on the mechanical connection between the strips and the pressure of the holding nut/bolts. after a period of time this can oxidise and increase the resistance of the connection and subsequantly restrict the current to the glow plugs. i removed mine and using a fine file cleaned them.
let me know if you need further clarification.
FollowupID: 349970

Reply By: greybeard - Wednesday, Jan 05, 2005 at 11:53

Wednesday, Jan 05, 2005 at 11:53
oops, re read the original post. If the motor starts ok when cold but not when hot I would suspect the following:
Cranking problem, cables, batteries etc ( not glow plugs )
if there was a problem with the fuel pump/injectors I would expect it to be a greater problem with starting ( more time for the fuel pressure to drop ) and/or rough running ( water, leaking/dirty injectors ).
When the motor is hot try operating the priming pump by hand until pressure is felt then try starting it. It may give you some idea about the state of the fuel system.

AnswerID: 91413

Follow Up By: Member - Davoe (WA) - Wednesday, Jan 05, 2005 at 12:13

Wednesday, Jan 05, 2005 at 12:13
I see what you mean now I thought you meant the mechanic had made improvements - not stuffed it up btw does that mechanic work for Toyota Kalgoorle now as his experise would be an improvement there :)
FollowupID: 349972

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