Two different Toyotas, two different queries...........

[Hilux Hetti]

Hi everyone. Been a member for a couple of weeks, but this is my first post. As you'll probably guess from my handle, I'm a female of advancing years, but have been working on cars, painting, pulling engines, honing, re-ringing etc for most of my life out of pure necessity. Bringing up two kids in the 70's with very little money made it so that I either fixed our old cars or we walked. With the help of some mechanically minded friend's husbands, I learned a lot over the years, but I'm stumped with the first issue below. I've been reading through lots of posts on here trying to find an answer to a couple of questions I have and am amazed at the knowledge here. Unfortunately, I couldn't find what I was wanting to know, so I thought I toss it up to the members in hope someone might be able to help..........

1) I recently bought a 1997 Hilux DX with a carby, 2.4 engine and coupled to a 5 speed manual. The engine was warm when I picked it up in Melbourne and drove it to my S/W Vic property. It ran well all the way, although heavier on fuel than I would have thought for a 5 speed manual, but that's an issue best left for another day. Two days after I bought it and after it had been parked outside all night, I drove it to work (30k's) for the first time. After a few k's cruising at 80kph (bad road, narrow and with lots of roos) it began to jerk back and forth quite violently. I soon found that if I put my foot down hard on the throttle, it would pick up well and run ok, but once I backed off to cruising speed, the jerking would begin again. Once out on the highway and cruising at 100kph, the jerking stopped, but throwing the clutch resulted in a rapid stall. Once the vehicle had been parked for a few minutes, it drove like a bought one. No problems at all. The air temp when starting out was around 3-4 degrees. The same thing happened the next time I drove it in the morning from a cold start and this is consistent on any cold day when driven from a cold start. The cold air intake flap near the radiator appears to be working, although it doesn't close fully leaving a gap of 4-6mm. Perhaps this is enough to direct a cold air flow to the carb? I really feel this is a cold temp issue or icing up of the carb on the cruise side of of the twin barrel carbie. On a warmer day, it starts and runs fine. Any input greatly appreciated.

Query 2) I have a 1990 Seca, 1600 coupled to a 3 speed auto. It's done almost 400,000k's without a spanner to either the engine or auto. I had the timing belt changed just over 12 months ago and the first thing I noticed after the belt change this time was that she had a much deeper exhaust note. Could it be that the mechanic let one of the cams slip a tooth? Perhaps it was already out a tooth and he corrected it? Unlikely I'd expect. Mechanics usually bugger stuff up, not correct it The car still goes fine without any apparent loss of power or economy.

The other thing with the Seca is when it changes gears, there's a definite flat spot, but not all the time. It's an intermittent thing, but very annoying, especially when I'm trying to power through crowded intersections. It's almost like someone pulled the coil lead out and put it straight back in. That's how bad the power drop is. I've checked all the leads and wiring, wiggling everything I could get my hands on with the engine running and I'm damned if I can make it do it. It only seems to occur when the vehicle is changing up through the gears. It's been doing it now for literally years and nobody can tell me what the likely cause might be.

Anyway, sorry for the lengthy first post. I promise to keep them shorter in future
Cheers,
Hetti.

[4th surf]

Hi Hetti, Welcome along but firstly I don't bugger stuff up, I fix it, well I try to anyway yet sometimes it's a little difficult when dealing with something that is for want of a better word "Shot" and a client who doesn't want to either listen or spend the money.

OK both of your questions from my point of view are a "Back to basics" type thing.

1. The Hilux. It probably needs a damn good tune up and a carby kit wouldn't go astray (rebuild the carb) so new plugs and leads, re-kit the carb and on the choke side of the carb you should find a round black thing with a wire attached. This is the "bi-metal body" which makes the choke work. This may be sticking but the way to check is to cold start with the air intake off and watch while it warms up. If the choke opens fully all is good there so would point to an air leak in the carby. So as said a good tune with carby kit and you're away.

2. 400km without a spanner near it then a timing belt done? Hell you should write to the pope about a miracle and get sainthood conferred on it.... Belt had most likely stretched over time and you became accustomed as to how the car ran and sounded. Mechanic has replaced the belt and returned timing to specs so she now has a (and excuse my french) bit more balls so as a result will sound a bit more "throaty" compared to what you're used to. As for the auto shifting. Well that's easy, as you have stated you only notice it under power on upshift. One of two things which will cause what you are noticing. Either the stator in the torque convertor has seized or it's flaring between shifts. Most people notice this as either a dead spot or a thumpy 1-2 shift. Place to start there is to change the auto fluid and if no different trans rebuild or good used auto is the way to go. Again remember first that the engine must be in good tune.

Hope that this helps.

By the way I'm an "old school" mechanic not one of these current day "parts fitters"

[thechuckster]

Hetti: the hilux carb could also have a low fuel level in the bowl (float valve at wrong height or simply full of gunk) - bouncy road gets the small amount of fuel aerated or simply stirs up the gunk - the jerking/bucking is it probably running lean. As 4th surf suggests: carbi kit, but also consider new fuel filter and have a look at the fuel pump.

If it's been offroaded a bit, just check that the tank capand the charcoal cannister setup is allowing the tank to breath.

Given that it seems to come on with cold starts - it does point to a lack of fuel.

[Hilux Hetti]

Thanks for the replies and I believe a couple of apologies are in order. The first due to the lack of detail in the heading of my post. I can only hope you'll forgive a newbie. Secondly, an apology to all the mechanics I invariably insulted. Personal experience in the past shouldn't cause me to believe all mechanics are incompetent and 'bugger stuff up." I do however own a Kombi as well and as any Kombi owner will tell you, there's few mechanics that touch them who don't bugger something up, but we won't go there :-)

4Surf. I actually wrote a much better post, probably longer that did explain that my timing belt has been changed at to correct intervals. Unfortunately it got deleted trying to post it and the second attempt was much shorter and left out that vital piece of information. It was changed at 120K (previous owner never bothered, so I did it as soon as I'd bought it), 220k and at 320k and it was only at the 320k change that the exhaust note go noticeably deeper, but as I said, it doesn't seem to have altered performance or fuel economy. I was just curious as to why it might happen and you explanation is as good as any I've heard.

As for a tune-up for the Hilux and maybe a carby kit, I must say that in all my years of having my head under a bonnet, I've never seen such a skinny set of plug leads. I can't believe they'd put things like that on an engine. I plan to dump them ASAP. It has done lots of miles too, into the 300,000k plus range, so the carby could probably use an overhaul. I've actually checked the operation of the automatic choke and it opens up in timely fashion and all the way open. An air leak? Yes, possible, so I think I'll take your advice and put a kit through the carby as soon as this rotten weather is over. I just can't get motivated to get outside at present, plus my shift work often interrupts my free time. Bursons for the carby kit, or directly to Toyota?

The Chuckster: Will check for breathing problems, yet it seems strange that as soon as you park the vehicle after a good warm-up, it starts and doesn't miss a beat after which I would confidently drive it to Darwin and back it runs so well. Kind of same with the above. I'd really expect that if it needed a kit, the problem would be there all the time, but it's only happens in really cold weather. On a fine day, it runs like a Swiss watch. The float level in the glass looks ok and it's easy to see. The engine has been steam cleaned by Car City and everyone is amazed as just how clean it is. I've seen near new cars with more dirt under the bonnet than this one.

The thing that made me suspect an icing problem is that I once owned a 1970 Mazda 1500 and it had a manual flap on the air intake. I set it to "summer" in the mistaken belief that more cold air was better for the engine. I was proved wrong on the first frosty night. It lost power, began to miss and I rolled to a stop on the side of the road in the middle of nowhere. I cursed and swore as I swung that starter and got nothing. No mobile phones in those days and two kids in the back. Bugger!! I sat around for awhile and in desperation tried it again and it started and ran beautifully........ for about 5k's and then died again. Then I remembered the "summer/winter" switch on the air intake, so using my cigarette lighter as a torch I turned it to "winter" and away it went and never missed a beat after that. This problem has all the same hallmarks, but a kit for the carby, new plugs, leads, filters etc and run a timing light over him and all the other things you suggested certainly can't hurt. I will sort it in due course. At least he has "character!!"

Cheers,
Hetti.

[George]

Seems like I can add something. I once had the situation when carby engine was literally jumping out of the bay at idle, and car had hunting and jerky behavior at cruise speed, but went ok as soon as I floored it. Turned out to be intake manifold air leak. The only difference is that in my case it was pretty consistent, but anyway checking for air leak won't take too much time. I use WD40 against suspicious places and check for changes in engine speed. When I get nothing, I repeat with plenty of water. If still no love, then there's no leak.

[4th surf]

Hetti 300km on the Hilux it's probably only just run in but changing the leads is part of a tune up. Carb kit Bursons or Repco. The fuel miser kits come with instructions to set the float level and to set the mixture you wind the mixture screw all the way in then out exactly 2 turns. Then when you start the car and run it up let it idle (750 rpm) and adjust the screw until it idles smoothest. set idle speed at 750rpm and done. Oh cold air= more dense air so more air into engine so improved volumetric efficiency and more power, effectively the job of forced induction (turbo) so there must've been an underlying problem there. I have experienced Iced up carbs before but one tends to notice that when the throttle jams wide open. You'll probably find the more throaty noise is due to the rear muffler dropping it's guts. Yes I remember the Combis and later models quite well. didn't mind working on them but for some reason for me finding reverse was another matter (bit like an R series Mack, got 15 gears forward, oh hang on lets try that switch, got 5 gears going backwards). Yet unlike working on a VW one tended to sh!t oneself working more on a Rolls-Royce. Yet one thing that I never worked out was why you were never seen by anyone you knew when taking either a Cloud, Shadow or Wraith for a road test. The Lada came in and for some reason it was my round at the pub.... Yes George I have worked on vehicles from your neck of the woods and I blame the NZ Dairy board for that "We'll sell you a lot of butter" (mid 80's just after the nuclear free thing) "Oh sorry the US won't let us pay you in cash so how about cars?"... I hated the damn things

[Hilux Hetti]

Thanks for the input George. All these things will be considered. The "beast" will run properly again in due course, even if I have to bite the bullet and take it somewhere to have it looked at. When it's warm, it runs superbly well. It just seems to hate the cold, but so do I which is mainly why I haven't been outside putting all the above ideas into play. I'm craving some decent weather here as I don't have a spare shed to put the Hilux in at present.

[Hilux Hetti]

No problems 4th Surf. There's a Burson's store not far from were I work and I mostly go there to get my common oil (Kombis use "Ace 30 or 40" or "Brad Penn") and the odd tool need to do a specialised job. Good people and reasonably priced. Two turns on the mixture screw. Gotcha.

Know what you mean about nobody noticing you when you're in a Roller. I've had a similar situation in reverse. I once had a friend who had a 62? Citroen Goddess. I considered it a particularly ugly car and really didn't want to be seen in it with her, but what happened almost every time she took me somewhere in it? Yep. Someone I knew would spot me. Must say though, it was a hell of a ride comfort wise!!

[lexsmaz]

Hi Hetti,

Its possible you could be on the money with the Hilux carby freezing, do you need to leave it turned off for minutes once its stalled or just a short time, i also have experienced a carby freezing but found it would thaw out in seconds & would drive fine after that, if it takes minutes for it to come good it good be a carby gasket issue etc & that needs time & the warmth to seal the air leak, next time it stalls hop out quickly & have a good look around the carby base / throttle area & look for signs of external icing, you should be able to see something ?? or at least feel around that area & if its really cold / freezing it could be the issue ..

Does the cold air flap have a stove pipe / hot air pipe running up to under neath the intake air flap, to direct heated air into the air cleaner ..

I cant picture these motors, do they have water heating to the manifolds too & are they all ok & connected & is it running at the correct operating temp & not to cold ??

[Dazza]

Try another thermostat in the Hilux. I have just had the same problem with my 86 Hilux. It nearly had me beat until i noticed the temp gauge was dropping back to cold when i slowed down on cold mornings. It ran fine at 100Ks but wouldnt idle or run any good at slow speeds on cold mornings. I think the thermostat must have been opening too early. I thought it must have been stuck open but it was closed when i pulled it out. It has run perfectly on cold mornings since changing the thermostat.

[George]

btw in my "neck of the woods" it's quite popular to boil thermostats with appropriate thermometers. So you can know fo sure 1) when it starts to open 2) when it opens fully and 3) if it opens smoothly

[Hilux Hetti]

Hi Hetti,

Its possible you could be on the money with the Hilux carby freezing, do you need to leave it turned off for minutes once its stalled or just a short time, i also have experienced a carby freezing but found it would thaw out in seconds & would drive fine after that, if it takes minutes for it to come good it good be a carby gasket issue etc & that needs time & the warmth to seal the air leak, next time it stalls hop out quickly & have a good look around the carby base / throttle area & look for signs of external icing, you should be able to see something ?? or at least feel around that area & if its really cold / freezing it could be the issue ..

Does the cold air flap have a stove pipe / hot air pipe running up to under neath the intake air flap, to direct heated air into the air cleaner ..

I cant picture these motors, do they have water heating to the manifolds too & are they all ok & connected & is it running at the correct operating temp & not to cold ??

When I said it stalls, I've never had to pull off the road as this only happens when I throw the clutch to change up a gear, so I simply select the right gear and slowly let the clutch out until the engine fires up again and I keep going. After a long drive, the condition will slowly disappear. Normally I only drive into town which is a 30 minute drive. By half way the jerking has stopped, but even once I've reached town the stall will occur when I throw the clutch. "Toeing" the brake whilst "heeling" the throttle ensures that it doesn't stop completely when at traffic lights, a driving style I'm uses to from years ago driving old bombs.

Although I haven't actually timed it, it doesn't appear to take long once stopped in town before the engine will start and drive beautifully and once in that condition, it doesn't miss a beat the rest of the day. It's as though the carby warms up from the heat of the engine and thaws out. And yes, it does have all the cold start stuff in place including the crinkly silver foil coated tube (don't know it's technical name) running from the exhaust manifold to the air intake behind the cold start flap which, as I've mentioned above, doesn't completely close when starting the engine from cold. It remains open 4-6mm. Enough to allow too much cold air through?

The inlet manifold is of a type that roughly the shape of the letter "C", but flattened on the driver's side. It has a web between the bulky area where the carby sits and the curves where it goes into the head. There's a larger part towards the front of the engine and the thermostat resides there, so I'm assuming the manifold has water channels cast into it. there are no external water pipes feeding warmth to the manifold as is seen in earlier cars.

Last week and with the evening air temperature around 8C, it started beautifully and ran well all the way into town. It's only on very cold days I get this problem.

[Hilux Hetti]

Try another thermostat in the Hilux. I have just had the same problem with my 86 Hilux. It nearly had me beat until i noticed the temp gauge was dropping back to cold when i slowed down on cold mornings. It ran fine at 100Ks but wouldnt idle or run any good at slow speeds on cold mornings. I think the thermostat must have been opening too early. I thought it must have been stuck open but it was closed when i pulled it out. It has run perfectly on cold mornings since changing the thermostat.

This is definitely a good place to start. I've noticed that the engine does reach the half way mark on the temp gauge, but it takes awhile to get there. The thermostat housing has red glue around the seal which looks like to original sealant used on Toyota engines. Is it possible it's done over 300,000klm without having the thermostat replaced????

This makes sense too for as I said in my last post, the thermostat housing is on the front end of the inlet manifold. That's such an easy one, that I'll get a new thermostat tomorrow if I can and give it a go.

I must add here that I appreciate all the help everyone has given me with regards to this matter. I will find the answer in due course. I'll eliminate possible faults one by one and let you know what the final answer was. Still a bit too cold and wet out to give it any serious attention at present. Problem solving also needs to fit around my semi casual work patterns.