Start-up and Initial Drive issue

schefferd May 25, 2013

  1. schefferd

    schefferd New Member

    Hi Everyone,

    I'm new to the forum, but I've searched around quite a bit before posting here. I've recently purchased a 2000 Land Cruiser 90 Diesel and I've got a few issues that I'm having trouble resolving. I didn't see anything like these in your forum, but I did see a lot of detailed and intelligent discussion so I am hoping someone here can give me some help.

    The first issue is the OBD Diagnostic port. I did not have a chance to test the OBD on this vehicle prior to purchase, and I'm finding it non-functional. The pin-out on the port doesn't match any posted standard. I had successfully tried out OBD readers on similar vehicles, so I'm curious to know if it is worth trying to rewire the port to match a known standard. Has anyone attempted anything like this? If not, how are DIY-minded folks pulling their engine codes?

    Now here is the real problem. I am getting an intermittent Check Engine light shortly after I start up on colder mornings. Once the check engine light turns on, there will be a short period where I have very little power, and the automatic transmission shifts oddly. Aside from the odd transmission behavior, this seems like LIMP mode. If I leave the truck running for a short while, or just drive it cautiously, there will be a sudden change. The engine will surge as if I had stomped on the pedal and released, then the vehicle runs like normal for the remainder of the day. This first happened in November, and was most pronounced if the vehicle hadn't been driven for a day or two. Colder weather was worse.

    I avoided driving it when I could, and ultimately changed out my fuel filter as a first step in problem solving. I had a new filter already since I planned to change it at 200K km, so I swapped it out early. My theory was that the fuel pump was struggling to build pressure, and maybe a clogged fuel filter was exacerbating it. Long story short, the problem went away with the new fuel filter.

    Until it came back. 6 months and many miles later, the problem resurfaced Monday morning. Long weekend with no driving, the engine turned over about 6 times before starting and then my check engine light popped on. 5 minutes later, everything was fine; I stopped and restarted the engine and the light stayed out.

    Now I'm thinking I'm back to my fuel pump. Maybe the new filter helped initially but it has slowly gotten a bit more clogged and the fuel pump has gotten a bit weaker? This is just a theory. I've got a bit of car know-how, but it is all based upon gas engines and this is my first diesel vehicle.

    Has anyone ever heard of anything like this? I'm about to take it back to the dealer, but after my last experience I really don't trust them. They pulled some engine codes for me when my brake pump failed and tried to sell me 4000 Euros worth of parts and labor instead of diagnosing to figure out which part failed and replacing it. I was able to talk them into giving me the codes so I could do my own research and work that time, but I'm not confident I will be able to do that again. Any information you can share will be greatly appreciated!

  2. wobbly

    wobbly Well-Known Member

    Couple of thoughts.

    Could be an air leak on the fuel line, which allows the fuel in the line to drop back into the tank.

    Or if its starting related, maybe a fault on the preheat circuit. This should stay on for a fair few seconds after startup, so you can check if there is 12v to the bar that connects the prehesat plugs.

    Neither would explain the check engine light though?

  3. Beau

    Beau Well-Known Member I am in guyana

    Pretty sure it's fuel related, which is causing the limp mode to come on and Te varying in power, possibilities are air in the system, clogged filters inside the main tank and fuel pump, weak fuel pump (never heard of this) or a failing spill control valve hence the long cranking times...

    There are some pins you can bring which will flag error codes in the dash, I don't know how to do it myself but someone will hopefully be along to tell you, start at the cheap ends and work your way back up, chek the filter in the pump, also worth checking vacuum lines at the back of the manifold
  4. schefferd

    schefferd New Member

    Well, the problem appears to have gone away now that the weather has warmed up. I checked the fuel filter when I changed it last November, and didn't notice any signs of the diesel bug, but that doesn't mean I don't have it, I guess. I read that there is an access panel to the fuel tank under the back seat; is that universal on all models, or only certain ones? Short of dropping the tank, how else would one check?

    Also, can anyone elaborate on the pin sets to pull the codes? I found instructions for an 80 Series, but I don't know if they'll work on a 90. I'm still debating rewiring the OBDII to see if I can get it to work with my reader. I know that some years of the Prado adhere to different standards on the port. Has anyone gotten their Prado to work with an OBDII device? There are only 5 wires in the harness, two of which are power; so there is a small finite number of combinations for me to try. If I knew which pins were used in the OBDII compliant wiring it would narrow the field considerably. Any ideas are welcome. Thanks,

  5. majic79

    majic79 Member

    The OBD port is not OBD2 compliant, so your readers won't work. When you flip the lid on the OBD port under the bonnet, there should be a pin diagram, you use Toyota Special Service tool (paper-clip) and bridge Te1 and E1 off the top of my head, when ign is on, the check engine light flashes - steady half-second interval on/off means no codes. if there's codes, then there'll be 0.2second interval flashes (count them) a half second pause, then more 0.2 second interval flashes (count them as well), the flash counts are a two digit code indicating the fault, if multiple codes are present, then there'll be a 1 second gap, then another set of two digit codes, all the codes are read out, then they will repeat. This is standard on all toyota's OBD ports prior to OBD2 (and some OBD2 have this in addition to the OBD2 scan port)
  6. schefferd

    schefferd New Member

    Hi All,

    I thought I would update this thread for anyone curious to know what was going on, or for anyone who comes along in the future with a similar issue. I got the code out, and it looks like the error code is: 78(8). Searching around on the internet seems to indicate this isn't an uncommon fault, and the fix action matches what they recommend at Toyota. Check out the high pressure fuel pump relay (04221-27012). Toyota Germany charges just over 300 Euros for this part (and another 200 for labor), and I've seen prices around 250 GBP for the part while browsing the internet.

    It does appear that there is an ECU check and a wire harness check that should be performed prior to replacing the relays. I'm off to perform those now, but my gut tells me that it is probably the pump element itself. The fact that the issue is non-drive-time dependent, rather than temperature or humidity makes me think that the high pressure isn't spooling as fast as the computer would like it to, hence the short LIMP mode on start-up, and then normal behavior for the remainder of the day.

    Armed with the code and the part number, I did find these other two links which may be of interest to future readers with a similar problem:

    www dot landcruiserclub dot net/forums/showthread.php/39958-My-Toyota-Land-Cruiser-won-t-accelerate-over-20-km-h
    www dot moranbahweather dot com/toyota/100series/lc_70_fzj10/rm/rm630e/m_di_0100.pdf

    I'm off to do some more tests, and then probably dropping too much money on what should otherwise be an inexpensive part. Does anyone know of any good online resellers in the UK or Germany where I might order that part (04221-27012)?

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